Why does “too many” sound wrong here?

I can’t believe I make too many mistakes in Turkish.

I’m a native English speaker trying help a friend understand why it sounds off to use “too many” here but I can’t seem to figure out why.

To me, “so many” sounds much better. Does anyone have a grammatical explanation for why it doesn’t really work with “too many”?

Solution 1:

Too equates to more than necessary, which isn't what you are wanting to say, apparently. So equates to very.

Notice that "I don't believe I make too many mistakes in Turkish" is perfectly normal; and "I don't believe I make so many mistakes in Turkish" sounds a bit odd.

So is a strengthening intensifier, and wants consistency from can't, which is also a strenghtened version of don't. Awkwardly, words that weaken the situation are also called intensifiers. Your sentence is trying to strengthen quantification of the mistakes, so can't and so work here. My sentence with don't is trying to weaken the quantification of the mistakes, so don't and too work as a pair.

Looked for, but didn't find, collocation data and analysis for verbs do, can and intensifiers too, so.

Solution 2:

This is idiomatic English meaning roughly ".. that I make many mistakes," The word "too" is just a concession admitting that some mistakes are made. For example, some of these "too often" phrases or this "We don't see that around here too often" likewise don't use "too" in the sense of "excessive."

Solution 3:

I think the reason it sounds off to you as a native is that it could be interpreted in a different way than intended.

I can't believe I make too many mistakes. => I don't think I make a lot of mistakes. I can't believe I make so many mistakes. => I think I make a lot of mistakes.