No language is ever truly phonetic, though countless people believe countless languages to be so. Some are a lot more phonetic than others, it's true, with English WELL down the list, but the rules are often quite intriguing. Anyone for Maltese, where the 'q' is a glottal stop, represented by ' in the following: qaqocc ('a'otcch, artichoke), qara baghli ('ara bali, courgettes), dqiq (d'i', flour)? Hungarian? Nagyfroccs (nadge-frotsch, white wine spritzer, heavy on the wine)? All phonetic -- once you know the rules.
That's before you start on the languages with different alphabets. Tibetan is quite fun. A friend of mine lived at sa.ngak.chos.dzong, the mighty spell-protected Dharma-fortress. My own view is that Tibetan is the most phonetic of all, as it was designed to transliterate Sanskrit, but the trouble is, that only applies with a pure Lhasa accent.
Cheers,
R.