"Go." is the shortest complete sentence in the English language ?

'Go.' is indeed a complete sentence in English. It is an imperative sentence with the implied subject 'you' (you go). Imperative sentences are grammatically complete even though the subject is often omitted. While there are shorter written 'sentences' like single letters or fragments, 'Go.' is considered the shortest complete grammatical sentence in English because it contains both a subject (implied) and a predicate.