Use espeak phone X-SAMPA to language-specific SAMPA foldings.

[hadware]

Currently, to get the language-specific SAMPA form of each phoneme, a working (and espeak-friendly) installation of mbrola is required.
This is problematic for several reasons:

• it requires an additional system-wide package install on linux platform (even though mbrola is available on most distributions)
• it requires the installation of a corresponding mbrola voice, which is either unpractical and/or quite heavy. Moreover, the entirety of the voice's speech data isn't actually used by espeak for the phonemization.
• the OSX/windows support for mbrola is very bad.

The foldings are all here: https://github.com/espeak-ng/espeak-ng/tree/master/phsource/mbrola

[hadware]

Additional note: https://github.com/espeak-ng/espeak-ng/blob/master/docs/mbrola.md#2-add-mbrola-phoneme-translation-file