Phonemize Japanese Language

[Miku AuahDark]

Describe the bug
Phonemizer can't be used to phonemize Japanese characters.

Phonemizer version

phonemizer-3.2.1
available backends: espeak-ng-1.52, segments-2.2.1
uninstalled backends: espeak-mbrola, festival

System
Windows 11 22H2 patch 1265

To reproduce

import phonemizer
print(phonemizer.phonemize("ほたる", language="ja", backend="espeak"))

Could not load the mbrola.dll file. is printed on the console followed by RuntimeError: failed to load voice "ja"

Expected behavior
Runs without problems.

Additional context
Running espeak-ng from command-line directly works.

C:\Users\MikuAuahDark>espeak-ng -q -x --ipa -v ja "ほたる"
ho̞tˈäɽɯᵝ

[Miku AuahDark]

Additional context
This LuaJIT script also properly able to return values same as the espeak-ng command-line, so phonemizer probably did something fancy regarding initialization?

local ffi = require("ffi")
local espeak = ffi.load("C:/Program Files/eSpeak NG/libespeak-ng.dll")

ffi.cdef[[
int espeak_Initialize(int output, int buflength, const char *path, int options);
const char *espeak_TextToPhonemes(const void **textptr, int textmode, int phonememode);
int espeak_SetVoiceByName(const char *name);
]]

local text = "ほたる"
-- 3 = allow espeakEVENT_PHONEME events AND espeakEVENT_PHONEME events give IPA phoneme names
print("espeak_Initialize", espeak.espeak_Initialize(2, 0, nil, 3))
print("espeak_SetVoiceByName", espeak.espeak_SetVoiceByName("ja"))

local temp = ffi.new("const char*[1]")
temp[0] = text
while temp[0] ~= nil do
	-- 1 = UTF-8 mode, 2 = bit 1 = IPA phonetic
	local result = espeak.espeak_TextToPhonemes(ffi.cast("const void**", temp), 1, 2)
	if result == nil then
		print("espeak_TextToPhonemes failed")
	end
	print("espeak_TextToPhonemes", ffi.string(result))
end

[Miku AuahDark]

Alright, found the issue.

I have to add this

if voice.identifier.startswith('mb'):
    continue

Before inserting it to the list of available languages:

phonemizer/phonemizer/backend/espeak/wrapper.py

Lines 239 to 241 in fd39cdc

 for voice in self.available_voices(): 
     if voice.language not in available: 
         available[voice.language] = voice.identifier 

In my eSpeak installation, MBROLA voices are listed first. Using LuaJIT, I was able to print list of the voices in order they're listed by espeak_ListVoices:

...
mb\mb-it2       italian-mbrola-2        it
mb\mb-jp1       japanese-mbrola-1       ja
mb\mb-jp2       japanese-mbrola-2       ja
mb\mb-jp3       japanese-mbrola-3       ja
jpx\ja  Japanese        ja
art\jbo Lojban  jbo
...