گپ (“gap”, or in Tajikistan “гап”) is a Persian word generally translated as “chat”. It has been loaned into several Turkic varieties, all of them in Central Asia (it does not appear in my Azerbaijani dictionary, for example, although I’m sure Iranian Turks use the word).
In Türkmenistan “gep” is in use on its own to mean “speech” and “geple(ş)mek” is in use for “to speak”. “GepLEmek” is used for “I speak English” or “he spoke”, while “gepLEŞmek” is used for “we were speaking [with one another]”. (“Sözlemek” also appears in my dictionary with the same reported English meaning, but “geplemek” is certainly more common.)
Unsurprisingly (unlike the absence in Azerbaijan, which is surprising indeed) “gap” is well represented in Uzbekistan. Here is what comes up on Zangori kema under “gap”:
gap 1 (Persian): saying, talk, words, expression; matter, subject; phrase, clause. ~ga aylantir- to talk into s.t. ~ni aylantir- to beat around the bush; to confuse the issue. unga ~ bakor kelmaydi or unga ~ kor/u hech kimga ~ bermaydi He never gives anyone a chance to talk; He never listens to anyone. ~ bilan kunni kech qil- to spend the whole day talking. ~ bilgancha ish bil Better to know how to do s.t. than just talk. ~ni bir yerga/~ bir joydan chiqdi Everyone was agreed. ~ bitta that’s final. ~ga bichgan/onasi ~ga tuqqan to be a born talker. ~ bo’l- to interrupt. bir ~ bo’lar Something will happen (to solve the predicament). ~ vaqt yo’qligida emas the point isn’t that there is no time. ~ gapir- to give a speech, to talk. ~ni gapir uqqanga speak to whoever may heed. ~ni ikki qil- to contradict, to disobey, not to heed. ~ini yo’qotib qo’y to lose track of what one is saying. ~ kelganda otangni ayama When it comes time to speak, spare no one, even your father. ~ga kir- to come around, to listen to reason; to begin speaking. ~ kovla- to stir up old problems. ~ga ko’n- to listen, to consent. ~ ko’p, ko’mir oz Talk is cheap. ~(ini) ol- to learn s.o.’s thoughts or intentions. ~ ola chiqdi Things fell apart; The matter ended in discord. ~ ot-/~ och- to begin speaking; to bring up. ~ini og’zidan ol-/~i og’zida qol- to stop short, to be left speechless. ~ning ochig’i actually, truth be known. ~ning po’st kallasi the truth of the matter (s. ~ga sol- to bring around, convince. ~ sot- to gossip, to chatter idly. ~ning tagiga yet- to get to the root of the matter. ~ning tagida ~ bor there’s a reason for everything. ~ tamom, vassalom end of story, that’s it. ~ tegiz-/~ida tur- to stick to one’s word. ~ga tut- to buttonhole. ~ga tush- to (begin to) speak. ~ga tushunadigan odam someone who understands what others want; someone easy to get along with. ~dan to’xta- to stop talking. ~ to’qi-/~ shu yerda qolsin Don’t let word of this get out. ~ chayna- to harp upon. ~ chaqishtir-/~dan chiq- to disobey, to cross. u mening ~imdan chiqmaydi He never disobeys me. ~dan ~ chiqib/~ chuvi- to busy o.s. with gossip. ~ni cho’z- to talk on and on. ~ Eshit- to get yelled at, to get bawled out. unga sizning ~ingiz o’tadi He listens to what you say. ~ini o’tkaz- to get one’s way. ~ o’g’irla-/~ qaytar- to talk back. uning ~iga qaraganda according to what he says. ~ qil- to make gossip, to make up rumors. ~ qistir- to interject. ~ni qisqa qil- to come to the point, not to waste time talking. ~ni ~ga qovushtirmaslik to let no one get a word in edgewise. bir ~dan qol- to lose (contest). katta ~ big deal, big accomplishment. nima ~? What’s up?; What’s the matter? shu ham ~ ekanmi? Big deal!, So what?, What an excuse! hamma ~ shunda that’s the whole problem. hech ~ yo’q Nothing’s going on.; Nothing has happened.
In the similarly Çağatay speech of Chinese Türkistan known as “Uyğur” one finds a similar enthusiasm for this particular Persian noun. Note in particular “گەپ كىرمەك” (gep kirmek), “kirmek” literally being “to enter” of course, but as a phrase it carries the meaning “to obey” or “to listen to” (perhaps “to take heed” would be a better translation?), and a similar effect is obtained with “گەپ ئۆتمەك” (gep ötmek), “ötmek” being “to pass”, both ideas being more or less mirrored in Zangori kema’s list above. Both lists are worth perusing in full. Also, both in Uzbekistan and Chinese Türkistan one encounters “gaplashmoq”/”گەپلەشمەك” (gepleşmek).
Interestingly, the term–while not surfacing in Eastern Kıpçak–also surfaces in Tatar (famously among the most Russified varieties of Turkic and further from the Persians geographically than the Eastern Kıpçaks) as “гәп” (gäp) and “гәпләшү” (gäpläşü). Tatars also use “gäp” in “гәп сату” (gäp satu), with a similar meaning to “gap sotmoq”/”گەپ ساتماق” (gep satmaq).
Broadly speaking, the word’s extance in a speaker community’s vocabulary and diversity in use reflects the level of direct contact with Iranian speakers. If I had to venture a guess to explain the distinction between Eastern Kıpçak and Tatar usage, I would say urbanisation was also an important factor. However this word should not be taken as a representation of Turkic treatment of Persian loanwords at large, as a similar Persian loanword, لاف (lâf) has a totally distribution: Widespread in Turkey, not used in the Republic of Azerbaijan, used in parts of Central Asia, but oftentimes as “lap/لاپ” so as to render its sound more Turkic (although in Uzbekistan “lof” is standard, and Tatars also say “laf”).