Abstract: A process for checking the Brazilian-Portuguese grammar of original text provided by a user. For each sentence, a token is generated to correspond to each of the words in the sentence. For each word in the sentence, an orthographic dictionary is searched to find possible variations in spelling, meaning and grammatical classification. Each token is expanded to include the variations in spelling, meaning and grammatical classification of its corresponding word. Each token is submitted to a heuristic process for excluding any variation which is incompatible with the token's juxtaposition within the sentence. Pre-analysis rules are applied to each token to identify and determine positionally correct alternatives for select pre-analysis errors in grammar based on the juxtaposition of each word within said sentence. An analysis tree, containing all of the tokens for the sentence and recording syntactic classification of the tokens and groups of tokens, is generated for the sentence.