Recently, I came across this quote, which brought back the famous debate of whether thought appears before language, or the latter is prerequisite for the former. Education implications are immense, and the question is at the centre of the Vygotsky-Piaget debate. Here is the quote:

Natural logic says that talking is merely an incidental process concerned strictly with communication, not with formulation of ideas. Talking... is supposed only to 'express' what is essentially already formulated... Formulation is an independent process, called thought or thinking and is supposed to be largely indifferent to the nature of particular languages. Languages have grammars which are assumed to be merely norms of conventional and social correctness, but the use of language is supposed to be guided... by correct, rational or intelligent thinking.

Cole and Scribner, quoted as 1940a, 207-208 (reference not found) in Hasan, Ways of saying: ways of meaning, Cassell (London), 1996, p. 19

The arguments are there - language requires thought, be it only because of its grammatical-rational conventions. Logic is natural and shared by everyone, language may inform the way to express logical thought.
However, I ask the reader: how many times have you found that you understood something more clearly after trying to explain it to someone else, or putting it down to paper? Language not only informs the way we express our thinking, it informs our very thinking. As a consequence, Cole and Scribner's first argument is a fallacy. Secondly, though I am no expert on language development, I believe it does not come entirely formed with grammatical structure. Piaget's development stages give a very strong case for a pre-language thought; however, I hold the child's perception of objects and shapes as a language, even though it is not an oral language: there are syntagms and, slowly, a grammar builds up with adjectives (such as colour, or other similarities between syntagms). Verbs come when action comes into play, and only then can any logic develop. An article in Brunner's Making Sense explains how children can start reasoning from the moment they realise their own influence on their environments, and thus a causal system.
That language was entirely embodied before words were formed does not make it less of a language. And it does come before thought.