One thing to keep in mind for subtitling projects is that certain languages require specific fonts. Not every font supports characters like umlauts or kanji. See the attachment on this article for a breakdown of which languages need which fonts.

If a client wants to use their specific branded font or another obscure font we don’t already have they will need to send us the font file as a TTF (preferred) or OTF, or they can reimburse us for buying it.