Japanese Language (Toyotomi)

Some ideas about Japanese romanization *there*.

At the time of Japanese-European contact, Japanese phonology still made the /dZi~Zi/ and /dzu~zu/ contrasts, in addition to having /kwa/ and /gwa/ syllables distinct from /ka/ and /ga/. There was also a contrast between /O:/ and /o:/. Modern /h/ was still pronounced /P/. The syllables /e/ and /o/ were [je] and [wo]. Modern /se/ was /Se/, as it still is in many dialects. I suspect that Japanese *there* would've retained /Se/ as the standard, as Japan *there* would retain the Kyoto region as its political center, instead of moving to the Kant&#333; region, which was a center of /se/ usage (a Portuguese description of Japanese, referring to the use of /se/, wrote that "people in Qvantô are notorious for such mispronunciations")

Portuguese Romanization appears to have been as follows: I do not know how they wrote /gi/ and /ge/.
 * Ô for /o:/
 * Ó for /O:/
 * C for /k/
 * qi, qe, qva for /ki/, /ke/, /kwa/
 * x for /S/
 * zu for /zu/
 * gi for /Zi/
 * dzu, zzu for /dzu/
 * tçu for /tsu/
 * ji for /dZi/
 * v for /w/

I don't suggest that the Portuguese version be adopted in toto. But, some of it may be adopted. A question arises - how conservative would romanization be? I see no reason, for example, to retain the /P/ pronunciation. However, would F be kept as the romanization, or would it change at some point to reflect the new pronunciation? And how would historic names be affected if it was changed? Would they continue being spelled in Western languages with F or with the new H?

Suggested early romanization
In the mid-17th century, a standard romanization was adopted by the Japanese government. The romanization followed the following conventions
 * Long vowels were marked by a circumflex
 * /O:/ was marked with Ó
 * /k/ was written C, or Q before /i/ and /e/ (later replaced with K)
 * /kw/ was written Qu
 * /g/ was written G, or Gh before /i/ and /e/
 * /S/ was written X
 * /Z/ was written J
 * /dZi/ was written Gi, other /dZ/ was written Gy
 * /tS/ was written Ch
 * /ts/ was written Ç
 * /P/ was written F
 * /j/ was written Y
 * /w/ was written V
 * The syllables /e/ and /o/ were written Ye and Vo (reflecting the pronunciation of the day)

I am not sure how the language itself would be pronounced in modern times, so I have no suggestions as yet for a modern romanization