I know I've already said that I'm deficient when it comes to learning languages--five years of Latin dribbled out of my head really quite quickly. When I was still in classes I could do what you're talking about--derive meaning from context in a number of languages with Latin roots, to the point where I could get the gist of simple things, and maybe subjects if the writing was complicated.

But I can't do that any more.

It's been too long since I used the skill, being that I am also an American and rarely if ever get a chance to interact with people who speak other languages. I can't even read simple Latin any more. I remember basics about the language--no punctuation, sentences end in verbs, the singular and plural of basic noun forms--but that's IT.

Now, I'm extremely language-learning deficient, and even though I know and accept this about myself, it's still frustrating. My brain just does not work that way.

So . . . I don't know. If the peer in question has experience in deriving context from meaning in other languages (I'm really good at it in English, just not in anything else), or is fluent or conversant in another language, then this is definitely a skill you should expect. On the other hand, there's me at the opposite end of the spectrum from you. Have patience.

(On a third hand, I'm guessing most people's language skills fall somewhere between ours. What that means re: deriving from context, I'm not sure.)