The fact that we're trying to quantify it, even as an academic exercise; a debate in the popular academic sense (as in both redundant and moot) relies on language. If the thoughts cannot be related in some understandable manner; they cannot be deemed anything coherent. It would be like saying to someone that you will now guess what they're thinking, and deciding that what they're thinking is wrong... and THAT gets us back to language.
It's not a chicken and the egg thing, you do not need to be able to manifest your thoughts in order to have them...so you need not to be able to communicate your thought in order to possess it.
Short hand of one of the nail in the coffin argument I used.
1.) Thoughts require concepts.*
2.) Concepts are not mind-independent. I.E. Concepts cannot exist unless there is someone to conceive of them.
3.) A unit of language must represent a referent, or describe a referent. Otherwise it'd be gibberish.
4.) [From 2.) and 3.)] Someone must conceive of an concept before it can be represented linguistically.
5.) Language require the concept of language.
---------
6.) Concept of language was conceived of prior to its linguistic representation.
7.) Concept of language existed prior to language.
Basically, before the first (wo)man created the first language, (s)he must have had a coherent concept of language. Albeit not as complex as language is today, but sufficient for the simple language that (s)he would have been familiar with and a coherent thought nonetheless.
*It can be composed of many other elements, but this is generally what is considered to be essential component and a coherent thought can be composed of concepts alone. It's actually quite an interesting topic, and if you want to read up on it, I recommend Donald Davidson's "Subjective, Intersubjective, Objective" and "Inquiries into Truth and Interpretation". He actually shares your position, which I don't think is as widely accepted as it once was. Quine and Wittgenstein both also touches on this subject, but they share my view and tend to appeal to more of an naturalistic approach instead of a purely philosophical one.