Adds Common Second Language quirk, tweaks to partial understanding (#90614)

## About The Pull Request

- Tweaks partial understanding. 

Paragraphs are now split into sentences first creating more natural
breaks between sentences.

- Adds "Common Second Language" quirk

This quirk changes your default understanding of common (up to) 90%
(your choice), meaning you drop the occasional word.


![image](https://github.com/user-attachments/assets/63e9d67b-7db2-4d23-9d0f-bae175962db4)


![image](https://github.com/user-attachments/assets/840ef391-5126-4ba7-9298-804686bcd6df)

Additionally, when your sanity drops below a threshold, you become
forced to speak your native language, albeit with a partial
understanding applied for everyone else.

Incompatible with similar language quirks + can't be taken by humans
(yet?)

## Why It's Good For The Game

Just a fun way to play around with the new "partial understanding"
system.

## Changelog

🆑 Melbert
add: "Common Second Language" quirk
qol: Language translations chunk sentences together better, making
partial understanding a bit easier to parse.
/🆑

code/__DEFINES/dcs/signals/signals_atom/signals_atom_movable.dm

@@ -138,4 +138,3 @@
 #define COMSIG_MOVABLE_BUMP_PUSHED "movable_bump_pushed"
 	/// Stop it from moving
 	#define COMPONENT_NO_PUSH (1<<0)
-

code/__DEFINES/say.dm

@@ -5,6 +5,8 @@
 #define RADIO_EXTENSION "department specific"
 #define RADIO_KEY "department specific key"
 #define LANGUAGE_EXTENSION "language specific"
+/// Message mod which contains a list of bonus "mutual understanding" to allow arbitrary understanding of any speech
+#define LANGUAGE_MUTUAL_BONUS "language mutual bonus"
 #define SAY_MOD_VERB "say_mod_verb"
 
 //Message modes. Each one defines a radio channel, more or less.

code/controllers/subsystem/processing/quirks.dm

@@ -23,7 +23,7 @@ GLOBAL_LIST_INIT_TYPED(quirk_blacklist, /list/datum/quirk, list(
 	list(/datum/quirk/social_anxiety, /datum/quirk/mute),
 	list(/datum/quirk/mute, /datum/quirk/softspoken),
 	list(/datum/quirk/poor_aim, /datum/quirk/bighands),
-	list(/datum/quirk/bilingual, /datum/quirk/foreigner),
+	list(/datum/quirk/bilingual, /datum/quirk/foreigner, /datum/quirk/csl),
 	list(/datum/quirk/spacer_born, /datum/quirk/item_quirk/settler),
 	list(/datum/quirk/photophobia, /datum/quirk/nyctophobia),
 	list(/datum/quirk/item_quirk/settler, /datum/quirk/freerunning),

code/datums/quirks/negative_quirks/csl.dm

@@ -0,0 +1,91 @@
+/datum/quirk/csl
+	name = "Common Second Language"
+	desc = "Common is not your native tongue - it's something you had to pick up along the way. \
+		Some words in common will sound foreign, and you may drift back to your native tongue \
+		when you are anxious or upset."
+	icon = FA_ICON_LANDMARK_DOME
+	quirk_flags = QUIRK_HIDE_FROM_SCAN
+	value = -2
+	gain_text = span_danger("You have difficulty parsing Common.")
+	lose_text = span_notice("Common starts to click for you.")
+	medical_record_text = "Patient is CSL."
+	/// What language typepath is our primary language?
+	var/native_language
+
+/datum/quirk/csl/add(client/client_source)
+	if(iscarbon(quirk_holder))
+		quirk_holder.remove_language(/datum/language/common, UNDERSTOOD_LANGUAGE, LANGUAGE_SPECIES)
+	else
+		quirk_holder.remove_language(/datum/language/common, UNDERSTOOD_LANGUAGE, LANGUAGE_ATOM)
+	quirk_holder.grant_partial_language(/datum/language/common, text2num(client_source?.prefs?.read_preference(/datum/preference/choiced/csl_strength)) || 90, type)
+	RegisterSignal(quirk_holder, COMSIG_SPECIES_GAIN, PROC_REF(reremove_common))
+	RegisterSignal(quirk_holder, COMSIG_MOB_SAY, PROC_REF(translate_parts))
+	native_language = get_native_language()
+
+/datum/quirk/csl/remove()
+	UnregisterSignal(quirk_holder, COMSIG_SPECIES_GAIN)
+	UnregisterSignal(quirk_holder, COMSIG_MOB_SAY)
+
+	if(QDELING(quirk_holder))
+		return
+
+	quirk_holder.remove_partial_language(/datum/language/common, type)
+	var/mob/living/carbon/carbon_quirk_holder = quirk_holder
+	if(istype(carbon_quirk_holder) && carbon_quirk_holder.dna.species)
+		// only give back common if they're a species that should speak it
+		var/datum/language_holder/species_holder = GLOB.prototype_language_holders[carbon_quirk_holder.dna.species.species_language_holder]
+		if(LAZYACCESS(species_holder.spoken_languages, /datum/language/common))
+			quirk_holder.grant_language(/datum/language/common, UNDERSTOOD_LANGUAGE, LANGUAGE_SPECIES)
+	else
+		quirk_holder.grant_language(/datum/language/common, UNDERSTOOD_LANGUAGE, LANGUAGE_ATOM)
+
+/datum/quirk/csl/is_species_appropriate(datum/species/mob_species)
+	var/datum/language_holder/species_holder = GLOB.prototype_language_holders[mob_species.species_language_holder]
+	if(isnull(species_holder))
+		return FALSE
+	if(length(species_holder.spoken_languages) < 2)
+		return FALSE
+	return ..()
+
+/// Gets our native language from our list of spoken languages
+/datum/quirk/csl/proc/get_native_language()
+	var/list/language_pool = quirk_holder.get_language_holder()?.spoken_languages?.Copy()
+	if(!length(language_pool))
+		return // no languages to pick from at all?
+
+	// Don't want this
+	language_pool -= /datum/language/common
+	// If we have native languages set, prefer them
+	var/list/prioritized_language_pool
+	var/obj/item/organ/tongue/tongue = quirk_holder.get_organ_by_type(/obj/item/organ/tongue)
+	if(length(tongue?.languages_native) > 0)
+		prioritized_language_pool = language_pool & tongue.languages_native
+
+	if(length(language_pool) < 1)
+		return // guess we couldn't find one
+
+	return length(prioritized_language_pool) > 0 ? prioritized_language_pool[1] : language_pool[1]
+
+// Every time we change species we need to re-remove common from our list
+/datum/quirk/csl/proc/reremove_common(...)
+	SIGNAL_HANDLER
+	quirk_holder.remove_language(/datum/language/common, UNDERSTOOD_LANGUAGE, LANGUAGE_SPECIES)
+	native_language = get_native_language()
+
+// At low sanity we translate everything to our native language
+/datum/quirk/csl/proc/translate_parts(datum/source, list/say_args)
+	SIGNAL_HANDLER
+
+	if(say_args[SPEECH_FORCED] || isnull(native_language) || quirk_holder.mob_mood?.sanity > 75)
+		return
+	// init this list if nothing else has
+	LAZYINITLIST(say_args[SPEECH_MODS][LANGUAGE_MUTUAL_BONUS])
+	// force speak language, add mutual bonuses so everyone else can understand
+	say_args[SPEECH_LANGUAGE] = native_language
+	say_args[SPEECH_MODS][LANGUAGE_MUTUAL_BONUS][native_language] = max(round(8 * sqrt(quirk_holder.mob_mood?.sanity), 5), say_args[SPEECH_MODS][LANGUAGE_MUTUAL_BONUS][native_language])
+
+/datum/quirk_constant_data/csl
+	associated_typepath = /datum/quirk/csl
+	customization_options = list(
+		/datum/preference/choiced/csl_strength,
+	)

code/game/atoms_movable.dm

@@ -1619,7 +1619,8 @@
 	return get_language_holder().get_random_understood_language()
 
 /// Gets a lazylist of all mutually understood languages.
-/atom/movable/proc/get_partially_understood_languages()
+/atom/movable/proc/get_partially_understood_languages() as /list
+	RETURN_TYPE(/list)
 	return get_language_holder().best_mutual_languages
 
 /// Gets a random spoken language, useful for forced speech and such.

code/game/machinery/telecomms/computers/logbrowser.dm

@@ -59,7 +59,7 @@
 					message_out = "\"[message_in]\""
 				else if(!user.has_language(language))
 					// Language unknown: scramble
-					message_out = "\"[language_instance.scramble_sentence(message_in, user.get_partially_understood_languages())]\""
+					message_out = "\"[language_instance.scramble_paragraph(message_in, user.get_partially_understood_languages())]\""
 				else
 					message_out = "(Unintelligible)"
 				packet_out["message"] = message_out

code/game/say.dm

@@ -272,8 +272,16 @@ GLOBAL_LIST_INIT(freqtospan, list(
 		return "makes a strange sound."
 
 	if(!has_language(language))
+		var/list/mutual_languages
+		// Get what we can kinda understand, factor in any bonuses passed in from say mods
+		var/list/partially_understood_languages = get_partially_understood_languages()
+		if(LAZYLEN(partially_understood_languages))
+			mutual_languages = partially_understood_languages.Copy()
+			for(var/bonus_language in message_mods[LANGUAGE_MUTUAL_BONUS])
+				mutual_languages[bonus_language] = max(message_mods[LANGUAGE_MUTUAL_BONUS][bonus_language], mutual_languages[bonus_language])
+
 		var/datum/language/dialect = GLOB.language_datum_instances[language]
-		raw_message = dialect.scramble_sentence(raw_message, get_partially_understood_languages())
+		raw_message = dialect.scramble_paragraph(raw_message, mutual_languages)
 
 	return raw_message
 

code/modules/antagonists/cult/blood_magic.dm

@@ -180,7 +180,7 @@
 	invocation = "Ta'gh fara'qha fel d'amar det!"
 
 /datum/action/innate/cult/blood_spell/emp/Activate()
-	owner.whisper(invocation, language = /datum/language/common)
+	owner.whisper(invocation, language = /datum/language/common, forced = "cult invocation")
 	owner.visible_message(span_warning("[owner]'s hand flashes a bright blue!"), \
 		span_cult_italic("You speak the cursed words, emitting an EMP blast from your hand."))
 	empulse(owner, 2, 5)
@@ -219,7 +219,7 @@
 
 /datum/action/innate/cult/blood_spell/dagger/Activate()
 	var/turf/owner_turf = get_turf(owner)
-	owner.whisper(invocation, language = /datum/language/common)
+	owner.whisper(invocation, language = /datum/language/common, forced = "cult invocation")
 	owner.visible_message(span_warning("[owner]'s hand glows red for a moment."), \
 		span_cult_italic("Your plea for aid is answered, and light begins to shimmer and take form within your hand!"))
 	var/obj/item/summoned_blade = new summoned_type(owner_turf)
@@ -293,7 +293,7 @@
 			span_cult_italic("You invoke the veiling spell, hiding nearby runes."))
 		charges--
 		SEND_SOUND(owner, sound('sound/effects/magic/smoke.ogg',0,1,25))
-		owner.whisper(invocation, language = /datum/language/common)
+		owner.whisper(invocation, language = /datum/language/common, forced = "cult invocation")
 		for(var/obj/effect/rune/R in range(5,owner))
 			R.conceal()
 		for(var/obj/structure/destructible/cult/S in range(5,owner))
@@ -311,7 +311,7 @@
 		owner.visible_message(span_warning("A flash of light shines from [owner]'s hand!"), \
 			span_cult_italic("You invoke the counterspell, revealing nearby runes."))
 		charges--
-		owner.whisper(invocation, language = /datum/language/common)
+		owner.whisper(invocation, language = /datum/language/common, forced = "cult invocation")
 		SEND_SOUND(owner, sound('sound/effects/magic/enter_blood.ogg',0,1,25))
 		for(var/obj/effect/rune/R in range(7,owner)) //More range in case you weren't standing in exactly the same spot
 			R.reveal()
@@ -413,7 +413,7 @@
 
 /obj/item/melee/blood_magic/proc/cast_spell(atom/target, mob/living/carbon/user)
 	if(invocation)
-		user.whisper(invocation, language = /datum/language/common)
+		user.whisper(invocation, language = /datum/language/common, forced = "cult invocation")
 	if(health_cost)
 		if(user.active_hand_index == 1)
 			user.apply_damage(health_cost, BRUTE, BODY_ZONE_L_ARM, wound_bonus = CANT_WOUND)

code/modules/antagonists/cult/cult_comms.dm

@@ -48,7 +48,7 @@
 	var/my_message
 	if(!message || !user.mind)
 		return
-	user.whisper("O bidai nabora se[pick("'","`")]sma!", language = /datum/language/common)
+	user.whisper("O bidai nabora se[pick("'","`")]sma!", language = /datum/language/common, forced = "cult invocation")
 	user.whisper(html_decode(message), filterproof = TRUE)
 	var/title = "Acolyte"
 	var/span = "cult italic"

code/modules/client/preferences/language.dm

@@ -83,3 +83,21 @@
 
 /datum/preference/choiced/language_skill/apply_to_human(mob/living/carbon/human/target, value)
 	return
+
+/datum/preference/choiced/csl_strength
+	category = PREFERENCE_CATEGORY_MANUALLY_RENDERED
+	savefile_key = "csl_strength"
+	savefile_identifier = PREFERENCE_CHARACTER
+	can_randomize = FALSE
+
+/datum/preference/choiced/csl_strength/create_default_value()
+	return "90%"
+
+/datum/preference/choiced/csl_strength/is_accessible(datum/preferences/preferences)
+	return ..() && (/datum/quirk/csl::name in preferences.all_quirks)
+
+/datum/preference/choiced/csl_strength/init_possible_values()
+	return list("90%", "75%", "50%", "33%", "25%", "10%")
+
+/datum/preference/choiced/csl_strength/apply_to_human(mob/living/carbon/human/target, value)
+	return

code/modules/language/_language.dm

@@ -225,6 +225,22 @@
 	if(length(last_sentence_cache) > SENTENCE_CACHE_LEN)
 		last_sentence_cache.Cut(1, last_sentence_cache.len - SENTENCE_CACHE_LEN + 1)
 
+/**
+ * Scramble a paragraph in this language.
+ *
+ * Takes into account any languages the hearer knows that has mutual understanding with this language.
+ */
+/datum/language/proc/scramble_paragraph(input, list/mutual_languages)
+	// perfect understanding, no need to scramble
+	if(mutual_languages?[type] >= 100)
+		return input
+
+	var/static/regex/first_sentence = regex(@"(.+?(?:[\.!\?]|$))", "g")
+	var/list/new_paragraph = list()
+	while(first_sentence.Find(input))
+		new_paragraph += scramble_sentence(trim(first_sentence.group[1]), mutual_languages)
+	return jointext(new_paragraph, " ")
+
 /**
  * Scrambles a sentence in this language.
  *
@@ -232,39 +248,54 @@
  */
 /datum/language/proc/scramble_sentence(input, list/mutual_languages)
 	var/cache_key = "[mutual_languages?[type] || 0]-understanding"
-	var/list/cache = read_sentence_cache(cache_key)
+	var/list/cache = read_sentence_cache(input)
 	if(cache?[cache_key])
 		return cache[cache_key]
 
-	var/list/real_words = splittext(input, " ")
+	// List of words that will be recombined into a sentence
 	var/list/scrambled_words = list()
-	for(var/word in real_words)
+	// List which indexes correspond to words in scrambled_words, records whether the word was translated
+	// Can't be a single assoc list because duplicates are expected
+	var/list/translated_index = list()
+	for(var/word in splittext(input, " "))
 		var/translate_prob = mutual_languages?[type] || 0
 		var/base_word = strip_outer_punctuation(word)
 		if(translate_prob > 0)
-			// the probability of managing to understand a word is based on how common it is
-			// 1000 words in the list, so words outside the list are just treated as "the 1500th most common word"
-			var/commonness = GLOB.most_common_words[LOWER_TEXT(base_word)] || 1500
-			translate_prob += (translate_prob * 0.2 * (1 - (min(commonness, 1500) / 500)))
+			// the probability of managing to understand a word is based on how common it is (+10%, -15%)
+			// 1000 words in the list, so words outside the list are just treated as "the 1250th most common word"
+			var/commonness = GLOB.most_common_words[LOWER_TEXT(base_word)] || 1250
+			translate_prob += (10 * (1 - (min(commonness, 1250) / 500)))
 			if(prob(translate_prob))
-				scrambled_words += base_word
+				scrambled_words += word
+				translated_index += FALSE
 				continue
 
-		scrambled_words += scramble_word(base_word)
+		var/scrambled_word = scramble_word(base_word)
+		scrambled_words += scrambled_word
+		translated_index += (scrambled_word != base_word)
 
 	// start building the new sentence. first word is capitalized and otherwise untouched
-	var/sentence = capitalize(popleft(scrambled_words))
-	for(var/word in scrambled_words)
-		if(prob(between_word_sentence_chance))
+	var/sentence = capitalize(scrambled_words[1])
+	for(var/i in 2 to length(scrambled_words))
+		var/word = scrambled_words[i]
+		// this was not translated so just throw it in
+		if(!translated_index[i])
+			sentence += " [word]"
+			continue
+		// if the last word was scrambled, always include a space
+		if(translated_index[i - 1] || prob(between_word_space_chance))
+			sentence += " "
+		// lastly try inserting a new sentence
+		else if(prob(between_word_sentence_chance))
 			sentence += ". "
 			word = capitalize(word)
-		else if(prob(between_word_space_chance))
-			sentence += " "
 
 		sentence += word
 
-	// scrambling the words will drop punctuation, so re-add it at the end
-	sentence += find_last_punctuation(input)
+	// scrambling the word will drop punctuation, so we need to re-add it at the end
+	// (however we don't need to do anything if the last word was not translated)
+	if(translated_index[length(scrambled_words)])
+		sentence += find_last_punctuation(input)
 
 	write_sentence_cache(input, cache_key, sentence)
 

code/modules/surgery/organs/internal/tongue/_tongue.dm

@@ -435,16 +435,15 @@
 	taste_sensitivity = 32
 	liked_foodtypes = GROSS | MEAT | RAW | GORE
 	disliked_foodtypes = NONE
-
-// List of english words that translate to zombie phrases
-GLOBAL_LIST_INIT(english_to_zombie, list())
+	// List of english words that translate to zombie phrases
+	var/static/list/english_to_zombie = list()
 
 /obj/item/organ/tongue/zombie/proc/add_word_to_translations(english_word, zombie_word)
-	GLOB.english_to_zombie[english_word] = zombie_word
+	english_to_zombie[english_word] = zombie_word
 	// zombies don't care about grammar (any tense or form is all translated to the same word)
-	GLOB.english_to_zombie[english_word + plural_s(english_word)] = zombie_word
-	GLOB.english_to_zombie[english_word + "ing"] = zombie_word
-	GLOB.english_to_zombie[english_word + "ed"] = zombie_word
+	english_to_zombie[english_word + plural_s(english_word)] = zombie_word
+	english_to_zombie[english_word + "ing"] = zombie_word
+	english_to_zombie[english_word + "ed"] = zombie_word
 
 /obj/item/organ/tongue/zombie/proc/load_zombie_translations()
 	var/list/zombie_translation = strings("zombie_replacement.json", "zombie")
@@ -453,20 +452,20 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 		var/list/data = islist(zombie_translation[zombie_word]) ? zombie_translation[zombie_word] : list(zombie_translation[zombie_word])
 		for(var/english_word in data)
 			add_word_to_translations(english_word, zombie_word)
-	GLOB.english_to_zombie = sort_list(GLOB.english_to_zombie) // Alphabetizes the list (for debugging)
+	english_to_zombie = sort_list(english_to_zombie) // Alphabetizes the list (for debugging)
 
 /obj/item/organ/tongue/zombie/modify_speech(datum/source, list/speech_args)
 	var/message = speech_args[SPEECH_MESSAGE]
 	if(message[1] != "*")
 		// setup the global list for translation if it hasn't already been done
-		if(!length(GLOB.english_to_zombie))
+		if(!length(english_to_zombie))
 			load_zombie_translations()
 
 		// make a list of all words that can be translated
 		var/list/message_word_list = splittext(message, " ")
 		var/list/translated_word_list = list()
 		for(var/word in message_word_list)
-			word = GLOB.english_to_zombie[LOWER_TEXT(word)]
+			word = english_to_zombie[LOWER_TEXT(word)]
 			translated_word_list += word ? word : FALSE
 
 		// all occurrences of characters "eiou" (case-insensitive) are replaced with "r"
@@ -501,6 +500,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	taste_sensitivity = 10 // LIZARDS ARE ALIENS CONFIRMED
 	modifies_speech = TRUE // not really, they just hiss
 	voice_filter = @{"[0:a] asplit [out0][out2]; [out0] asetrate=%SAMPLE_RATE%*0.8,aresample=%SAMPLE_RATE%,atempo=1/0.8,aformat=channel_layouts=mono [p0]; [out2] asetrate=%SAMPLE_RATE%*1.2,aresample=%SAMPLE_RATE%,atempo=1/1.2,aformat=channel_layouts=mono[p2]; [p0][0][p2] amix=inputs=3"}
+
 // Aliens can only speak alien and a few other languages.
 /obj/item/organ/tongue/alien/get_possible_languages()
 	return list(
@@ -557,6 +557,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	modifies_speech = FALSE
 	liked_foodtypes = VEGETABLES
 	disliked_foodtypes = FRUIT | CLOTH
+	languages_native = list(/datum/language/calcic)
 
 /obj/item/organ/tongue/robot
 	name = "robotic voicebox"
@@ -611,6 +612,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	attack_verb_continuous = list("shocks", "jolts", "zaps")
 	attack_verb_simple = list("shock", "jolt", "zap")
 	voice_filter = @{"[0:a] asplit [out0][out2]; [out0] asetrate=%SAMPLE_RATE%*0.99,aresample=%SAMPLE_RATE%,volume=0.3 [p0]; [p0][out2] amix=inputs=2"}
+	languages_native = list(/datum/language/voltaic)
 
 // Ethereal tongues can speak all default + voltaic
 /obj/item/organ/tongue/ethereal/get_possible_languages()
@@ -623,6 +625,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	liked_foodtypes = SEAFOOD | ORANGES | BUGS | GORE
 	disliked_foodtypes = GROSS | CLOTH | RAW
 	organ_traits = list(TRAIT_WOUND_LICKER, TRAIT_FISH_EATER)
+	languages_native = list(/datum/language/nekomimetic)
 
 /obj/item/organ/tongue/jelly
 	name = "jelly tongue"
@@ -631,6 +634,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	liked_foodtypes = MEAT | BUGS
 	disliked_foodtypes = GROSS
 	toxic_foodtypes = NONE
+	languages_native = list(/datum/language/slime)
 
 /obj/item/organ/tongue/jelly/get_food_taste_reaction(obj/item/food, foodtypes = NONE)
 	// a silver slime created this? what a delicacy!
@@ -644,6 +648,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	say_mod = "chimpers"
 	liked_foodtypes = MEAT | FRUIT | BUGS
 	disliked_foodtypes = CLOTH
+	languages_native = list(/datum/language/monkey)
 
 /obj/item/organ/tongue/moth
 	name = "moth tongue"
@@ -652,11 +657,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	liked_foodtypes = VEGETABLES | DAIRY | CLOTH
 	disliked_foodtypes = FRUIT | GROSS | BUGS | GORE
 	toxic_foodtypes = MEAT | RAW | SEAFOOD
-
-/obj/item/organ/tongue/zombie
-	name = "rotting tongue"
-	desc = "Makes you speak like you're at the dentist and you just absolutely refuse to spit because you forgot to mention you were allergic to space shellfish."
-	say_mod = "moans"
+	languages_native = list(/datum/language/moffic)
 
 /obj/item/organ/tongue/mush
 	name = "mush-tongue-room"
@@ -664,6 +665,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	icon = 'icons/obj/service/hydroponics/seeds.dmi'
 	icon_state = "mycelium-angel"
 	say_mod = "poofs"
+	languages_native = list(/datum/language/mushroom)
 
 /obj/item/organ/tongue/pod
 	name = "pod tongue"
@@ -673,6 +675,7 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	disliked_foodtypes = GORE | MEAT | DAIRY | SEAFOOD | BUGS
 	foodtype_flags = PODPERSON_ORGAN_FOODTYPES
 	color = COLOR_LIME
+	languages_native = list(/datum/language/sylvan)
 
 /obj/item/organ/tongue/golem
 	name = "golem tongue"
@@ -684,3 +687,4 @@ GLOBAL_LIST_INIT(english_to_zombie, list())
 	liked_foodtypes = STONE
 	disliked_foodtypes = NONE //you don't care for much else besides stone
 	toxic_foodtypes = NONE //you can eat fucking uranium
+	languages_native = list(/datum/language/terrum)

tgstation.dme

@@ -1941,6 +1941,7 @@
 #include "code\datums\quirks\negative_quirks\chronic_illness.dm"
 #include "code\datums\quirks\negative_quirks\claustrophobia.dm"
 #include "code\datums\quirks\negative_quirks\clumsy.dm"
+#include "code\datums\quirks\negative_quirks\csl.dm"
 #include "code\datums\quirks\negative_quirks\cursed.dm"
 #include "code\datums\quirks\negative_quirks\deafness.dm"
 #include "code\datums\quirks\negative_quirks\depression.dm"

tgui/packages/tgui/interfaces/PreferencesMenu/preferences/features/character_preferences/language.tsx

@@ -21,3 +21,9 @@ export const language_skill: FeatureChoiced = {
   description: 'The percentage of the language you can understand.',
   component: FeatureDropdownInput,
 };
+
+export const csl_strength: FeatureChoiced = {
+  name: 'Language Skill',
+  description: 'The percentage of Common you can understand.',
+  component: FeatureDropdownInput,
+};