I am a DM of a small group of friends; we prefer D&D 5e but this question can apply to any TTRPG. My friends have some experience with English, but are not comfortable with it. Lately I've been entertaining an idea of "helping" them become more comfortable with it using D&D.
My draft plot is as follows:
Their characters find themselves in an unfamiliar realm of which they heard little but with which language they have some experience with. The game will be held in their native language, but all the NPCs will speak only in English; literature, notes etc. will be completely in English. My idea is that they will be gently "forced" to interact with characters in English, which would allow them to grow their skill organically, much like some people learn local language when they are forced to live abroad. Players would know what they are signing up for upfront.
Is it a good idea for players to not understand what NPCs are saying, at least for a while? Would it be fun to be "weak" in this way, or would it be too stressful? Can that prevent them from interacting with NPCs altogether? Is there any real educational value in it? I am thinking about giving them a "magic" dictionary early on (Google Translate); would that defeat the purpose?