橘花: きっか or きつか? When つ in compound words turns into っ?


I can't find any grammar rules about transformation of つ in っ in compound
words. For example 橘花 (WW2 japanese jet). 橘 is きつ and 花 is か. Pronunciation is
not きつか but きっか (some people say きつか is ok too, but きっか is actually right). Or
words with kanji 絶 (ぜつ): 絶望 (ぜつぼう), 絶滅 (ぜつめつ), but 絶息 (ぜっそく), 絶交 (ぜっこう). Can
anyone explain please?




These are instances of [sokuon](https://en.wikipedia.org/wiki/Sokuon)
(consonant gemination).

Unfortunately, there aren't any simple go-to predictive grammar rules that
explain the phenomenon of consonant gemination in Japanese (check
[here](https://en.wikipedia.org/wiki/Gemination#Japanese)). As explained on
Wiki [here](https://en.wikipedia.org/wiki/Japanese_phonology#Gemination_2), つ
and く are sometimes converted to a geminate consonant (marked by the small
tsu) when they occur mid-word. This happens in some words (絶交 ze **kk** ou, 絶息
ze **ss** oku) and not in others (絶滅 zetsumetsu, 絶望 zetsubou) depending on the
phonemic environment within the word. It's definitely an interesting aspect of
Japanese linguistics but it would require some dedicated study to understand
the complexity of the rules which determine these changes. If you are just
looking to learn which words it happens in and which it doesn't, it's probably
more practical to just learn them case by case.

#

This is discussed in some detail in these answers, which you might find
useful:

  * [How did "little tsu" become a lengthener?](https://japanese.stackexchange.com/questions/751/how-did-little-tsu-become-a-lengthener)
  * [とっても versus とても](https://japanese.stackexchange.com/questions/808/%e3%81%a8%e3%81%a3%e3%81%a6%e3%82%82-versus-%e3%81%a8%e3%81%a6%e3%82%82)




These are instances of [sokuon](https://en.wikipedia.org/wiki/Sokuon)
(consonant gemination).

Unfortunately, there aren't any simple go-to predictive grammar rules that
explain the phenomenon of consonant gemination in Japanese (check
[here](https://en.wikipedia.org/wiki/Gemination#Japanese)). As explained on
Wiki [here](https://en.wikipedia.org/wiki/Japanese_phonology#Gemination_2), つ
and く are sometimes converted to a geminate consonant (marked by the small
tsu) when they occur mid-word. This happens in some words (絶交 ze **kk** ou, 絶息
ze **ss** oku) and not in others (絶滅 zetsumetsu, 絶望 zetsubou) depending on the
phonemic environment within the word. It's definitely an interesting aspect of
Japanese linguistics but it would require some dedicated study to understand
the complexity of the rules which determine these changes. If you are just
looking to learn which words it happens in and which it doesn't, it's probably
more practical to just learn them case by case.

#

This is discussed in some detail in these answers, which you might find
useful:

  * [How did "little tsu" become a lengthener?](https://japanese.stackexchange.com/questions/751/how-did-little-tsu-become-a-lengthener)
  * [とっても versus とても](https://japanese.stackexchange.com/questions/808/%e3%81%a8%e3%81%a3%e3%81%a6%e3%82%82-versus-%e3%81%a8%e3%81%a6%e3%82%82)

