How did "little tsu" become a lengthener?


How did it come about historically that
[っ](http://en.wikipedia.org/wiki/Little_tsu) preceding a sound would geminate
it? Is it really a little つ or are they just near homomorphs?




This question should be broken into two different questions:

>   1. When and how did small-tsu come to represent consonant gemination.
>   2. When and how did consonant gemination (as represented by small-tsu)
> come to be in Japanese.
>

(For those who don't know the term:
[gemination](http://en.wikipedia.org/wiki/Gemination) simply means doubling of
sounds, usually consonants. It's easy to get the sense once you see it comes
from the same Latin root as Gemini).

The answer for the first question is simpler, and was already given: in
[historical kana usage](http://en.wikipedia.org/wiki/Historical_kana_usage),
consonant gemination was originally represented either by a full-size つ or by
another consonant that got elided (usually that would be く, as in 学校, which
was written ガクカウ in old spelling, or き as in 石鹸, originally: セキケン). The small-
tsu spelling is recent. It was used sometimes even in the 19th century to
indicate that the sound got elided, if not earlier, but small kana letters
became a standard only following the 1946 spelling reform.

The answer for the second question is trickier. I don't have any historical
linguistics books that I can check to get a definite answer for when the
change happened, but it couldn't be earlier than the Heian period, and it was
probably earlier than the 17th century. The reason for the change was quite
simple: it happened in places where the sounds く and つ were already pronounced
without the vowel (as still happens today in words such a ドクター and いつか which
are usually pronounced `[doktaa]` and `[itska]`).

From here, the process that happened is quite simple: in words like 学校 the
gemination was already there once the vowel disappeared and the word was
pronounced `[gakkou]`. In words like 血気, `[ketuki]` (you have to remember that
つ was originally pronounced [tu]) became `[ketki]` and the `/t/` became
assimilated to `/k/`, so in the end we got `[kekki]`.

There are also some cases where the gemination was not caused by an elided
consonant, but from the elision of a long vowel (like [真赤]{まあか} `[maaka]`,
which became [真っ赤]{まっか} `[makka]`) or just because speakers decided to make
the word longer for emphasis or some other reason (that's what happened in
きっと, which was originally きと). These spontaneous geminations [still happen
today](https://japanese.stackexchange.com/questions/808/versus).




This question should be broken into two different questions:

>   1. When and how did small-tsu come to represent consonant gemination.
>   2. When and how did consonant gemination (as represented by small-tsu)
> come to be in Japanese.
>

(For those who don't know the term:
[gemination](http://en.wikipedia.org/wiki/Gemination) simply means doubling of
sounds, usually consonants. It's easy to get the sense once you see it comes
from the same Latin root as Gemini).

The answer for the first question is simpler, and was already given: in
[historical kana usage](http://en.wikipedia.org/wiki/Historical_kana_usage),
consonant gemination was originally represented either by a full-size つ or by
another consonant that got elided (usually that would be く, as in 学校, which
was written ガクカウ in old spelling, or き as in 石鹸, originally: セキケン). The small-
tsu spelling is recent. It was used sometimes even in the 19th century to
indicate that the sound got elided, if not earlier, but small kana letters
became a standard only following the 1946 spelling reform.

The answer for the second question is trickier. I don't have any historical
linguistics books that I can check to get a definite answer for when the
change happened, but it couldn't be earlier than the Heian period, and it was
probably earlier than the 17th century. The reason for the change was quite
simple: it happened in places where the sounds く and つ were already pronounced
without the vowel (as still happens today in words such a ドクター and いつか which
are usually pronounced `[doktaa]` and `[itska]`).

From here, the process that happened is quite simple: in words like 学校 the
gemination was already there once the vowel disappeared and the word was
pronounced `[gakkou]`. In words like 血気, `[ketuki]` (you have to remember that
つ was originally pronounced [tu]) became `[ketki]` and the `/t/` became
assimilated to `/k/`, so in the end we got `[kekki]`.

There are also some cases where the gemination was not caused by an elided
consonant, but from the elision of a long vowel (like [真赤]{まあか} `[maaka]`,
which became [真っ赤]{まっか} `[makka]`) or just because speakers decided to make
the word longer for emphasis or some other reason (that's what happened in
きっと, which was originally きと). These spontaneous geminations [still happen
today](https://japanese.stackexchange.com/questions/808/versus).

