Thousand year old vampire - Checking Skills

First time player and eager to start. I have a question about skills though: When I understand it correctly, I am supposed to check a skill when I use it. My character was a teacher and has mastered 4 languages. So if there is prompt, where I meet a travelling monk and converse with him in Latin (which would fit my character), am I supposed to check the skill (even though the prompt did not tell me to check a skill) and won't be allowed to speak another language again? When I use my skills in this way, I may be out of skills to check by prompt 5. So I would die if the game wants me to check a skill?