Quotes should be presented verbatim, whether they were originally spoken in English or translated into English from another language. Note that verbatim does not necessarily mean word for word, when translated. Translators should take care to retain the emotion, style and word choice of quotes to best reflect the speaker.
In general, minor grammatical errors or deviations in quotes should remain as is. Paraphrase quotes that lack clarity because of significant grammatical errors or deviations.
Quotes must be used judiciously, to ensure each source dignity and reader clarity.