Hi, I'm sure that some of you will now the answer,
Are there any rules to anticipe the reading of 2 kanjis if the first one ends in ... 　溌　はtsu.. 学　がku　..and maybe others endings and the next kanji starts with ka, ke, ki, ko, ku sounds and sa ,shi ,se ,so ,po,!! Examples 発車hassha instead of hatsusha　、学校 gakkou instead of gakukou?
Thanks in Advance!!

If there is a rule, I bet it's one of those ones that no native speaker could explain or would have ever thought about. Trying to apply a rule probably takes more mental effort than just learning the words.

(sorry for not actually answering your question at all...)

I don't know if there is a rule to it, but it seems to follow a certain logic probably based on the ease of pronounciation. At least I have started to intuitively "predict" this logic and often it just makes sense to drop parts of the reading for a simpler pronounciation.

In your examples the readings together can create a double consonant which makes the reading easier to pronounce than if the vowel was kept intact. Think about how bothersome it is to pronounce "gakukou" instead of "gakkou". But there are still exceptions, like ryokakuki (passenger plane) iirc. I think even then in speech the u drops.

We do this in Finnish all the time too.

I read years ago that scholars only found rules for the cases in which the contraction doesn't happen, but I cannot link to the study because I didn't keep it (however, maybe I read it on this forum, so you could try the search function).

As stated above, contractions are done for ease of pronounciation, so you can likely predict most of those.

Thanks for your replies , so far I've distinguished the following changes in the pronunciations;

in the ATSU,ITSU,ETSU,OTSU,UTSU endings:

batsu /datsu/gatsu/hatsu/katsu/matsu/ratsu/satsu /tatsu/zatsu.
etsu/ betsu /getsu/ketsu/metsu/netsu/retsu/setsu/tetsu /zetsu.
otsu/botsu/hotsu/kotsu/motsu/sotsu/totsu
utsu/butsu/futsu /jutsu/kutsu/shutsu
itsu/chitsu/hitsu//jitsu /kitsu/mitsu/ritsu/shitsu

Contrations if followed by KA..KI..KU..KE..KO.., SA..SHI..SU..SE..SO.. , PA..PU..PO.. , TA..TO..TE, CHA..CHU..SHO.. and others??

In the AKU , IKU , OKU , UKU ending:

aku/baku/chaku/daku/gaku/haku/jaku/kaku/maku/raku/saku/shaku/taku
iku/chiku/jiku/kiku/niku/riku
oku/boku/choku/doku /goku/hoku/joku/koku/moku/roku/soku/shoku/toku/zoku
fuku/juku/shuku

Contrations if followed by KA..KI..KU..KE..KO.., and others?

so there must be a pronunciation rule about it.

I don't understand why you detail that much. Say you consider a disyllable, composed of an initial and a final part, when two disyllables meet in a compound:

final つ + initial sh/s　> double sh/s
final つ + initial h/f* > double p (not from ぱ/ぷ/ぽ like you said)
final く + initial k > double k**

*final つ　+ initial b doesn't do it anything, probably because b is already voiced
** u falls, like often, the most central vowel isn't pronounced (see French silent e)
again g > double g doesn't happen because g voiced

Note sh/s, h/f, k are all voiceless sounds. っ also seems to naturally work with voiceless and not voiced sounds (って vs っd, all the double d come from foreign words).

EratiK Wrote:There's no need to detail that much. Say you consider a disyllable, composed of an initial and a final part, when two disyllables meet in a compound:

final つ + initial sh/s　> double sh/s
final つ + initial h/f* > double p (not from ぱ/ぷ/ぽ like you said)
final く + initial k > double k**

*final つ　+ initial b doesn't do it anything, probably because b is already voiced
** u falls, like often, the most central vowel isn't pronounced (see French silent e)
again g > double g doesn't happen because g voiced

Note sh/s, h/f, k are all voiceless sounds. っ also seems to naturally work with voiceless and not voiced sounds (って vs っd, all the double d come from foreign words).

く also geminates h-f sometimes, doesn't it? I'm thinking of 六百, for example. Likewise, ち also works: 八百.

Sometimes you get rendaku instead, too: the Tokugawa Shogunate is not the *Tokkawa Shogunate.

Edit: never mind, I was completely wrong.

Vempele Wrote:

poblequadrat Wrote:Sometimes you get rendaku instead, too: the Tokugawa Shogunate is not the *Tokkawa Shogunate.

That's because those are both kun'yomi.

But what about 突っ込む? And 三日? (add つ+k- > kk... sometimes.)

This doesn't have anything to do with the writing system; it's an issue of pronunciation. It occurs more often with Chinese loans than with native Japanese words but it happens with both.

poblequadrat Wrote:

Vempele Wrote:

poblequadrat Wrote:Sometimes you get rendaku instead, too: the Tokugawa Shogunate is not the *Tokkawa Shogunate.

That's because those are both kun'yomi.

My dictionary lists とく as an onyomi.

Yes, that "toku" is a Buddhist loan term from Chinese; the Middle Chinese pronunciation of 徳 was *tək.

Okay, how about "because they're both words in their own right" instead? That was actually the reason I assumed it was a kun'yomi without checking (oops).

Usually the voiced syllables in this kind of case are remnants of の, i.e. toku no kawa -> tokunkawa -> tokugawa.

But I don't know, are there any examples of ku + ka -> kk? I know of a name そっけん which is 足 + 軒. EDIT: 六巻

yudantaiteki Wrote:But I don't know, are there any examples of ku + ka -> kk? I know of a name そっけん which is 足 + 軒. EDIT: 六巻

閣下, 国家, 薬価...

Vempele Wrote:Okay, how about "because they're both words in their own right" instead? That was actually the reason I assumed it was a kun'yomi without checking (oops).

Well, to be fair rendaku only happens in kun-compounds... (with exceptions).
That's very interesting that old の turns into rendaku!