Why is debug デバッグ but bug is バグ?


I'm interested in why the extra small tsu in included in the word デバッグ but not
バグ.

[Are there any rules governing voicing in words formed via
reduplication?](https://japanese.stackexchange.com/questions/13059/are-there-
any-rules-governing-voicing-in-words-formed-via-reduplication/13065#13065)

[Lyman's rule](https://japanese.stackexchange.com/questions/13059/are-there-
any-rules-governing-voicing-in-words-formed-via-reduplication/13065#13065) may
explain this, but does anyone know any more information on why the triple
voiced compound is resolved by adding a small tsu (like maybe why a long sound
or something different isn't used)




I'm fairly certain that this has to do with pitch in Japanese and accentuation
in English.

The natural pitch for デバグ【HLL】 is HLL, whereas デバッグ【LHLL】 would naturally be
LHL (and バグ【HL】 is HL). To mimic accentuation by pitch (i.e. accented
syllables get a high pitch after transliteration), the ッ is necessary to give
the バ a (natural) high pitch. バグ already has the right pitch pattern and the
best pronunciation approximation to "bug".

(Besides, バッグ is already a word, although here the ッ is probably used to
imitate the /æ/ sound, like in キャ **ッ** シュ "cash".)

So both バグ and デバッグ are to be the expected transliterations, and either pair
バッグ/デバッグ and バグ/デバグ has shortcomings, albeit being more consistent in some
sense.

**Update 2022**. Darius Jahandarie points out that nowadays _katakana_
loanwords (especially computer/tech-related terms) are increasingly often
pronounced with the _heiban_ (平板) pitch accent (see [Wikipedia on Japanese
pitch accent](https://en.wikipedia.org/wiki/Japanese_pitch_accent) for a brief
description), so that the pitch accents for the two words in question would be
バグ【LH】 and デバッグ【LHHH】.




I'm fairly certain that this has to do with pitch in Japanese and accentuation
in English.

The natural pitch for デバグ【HLL】 is HLL, whereas デバッグ【LHLL】 would naturally be
LHL (and バグ【HL】 is HL). To mimic accentuation by pitch (i.e. accented
syllables get a high pitch after transliteration), the ッ is necessary to give
the バ a (natural) high pitch. バグ already has the right pitch pattern and the
best pronunciation approximation to "bug".

(Besides, バッグ is already a word, although here the ッ is probably used to
imitate the /æ/ sound, like in キャ **ッ** シュ "cash".)

So both バグ and デバッグ are to be the expected transliterations, and either pair
バッグ/デバッグ and バグ/デバグ has shortcomings, albeit being more consistent in some
sense.

**Update 2022**. Darius Jahandarie points out that nowadays _katakana_
loanwords (especially computer/tech-related terms) are increasingly often
pronounced with the _heiban_ (平板) pitch accent (see [Wikipedia on Japanese
pitch accent](https://en.wikipedia.org/wiki/Japanese_pitch_accent) for a brief
description), so that the pitch accents for the two words in question would be
バグ【LH】 and デバッグ【LHHH】.

