There is a distinction in meaning between infer and imply. In the sentence the speaker implied that the General had been a traitor, implied means that something in the speaker's words suggested that this man was a traitor (though nothing so explicit was actually stated). However, in we inferred from his words that the General had been a traitor, inferred means that something in the speaker's words enabled the listeners to deduce that the man was a traitor. The two words infer and imply can describe the same event, but from different angles. Mistakes occur when infer is used to mean imply, as in are you inferring that I'm a liar? （instead of are you implying that I'm a liar?）. The error is common enough for some dictionaries to record it as a more or less standard use: over 20 per cent of citations for infer in the British National Corpus are erroneous for imply.