You can get any lawyer, judge or Canadian embassy official in the country you live (if not in Canada) to sign you an affidavit if you, a relative or a friend is doing the translation. An affidavit is basically a statement by the translator that the translation is a faithful representation of the original document's contents into the other language (English or French), so he/she signs it in front of the official serving as commissioner of oaths (lawyer, judge or Canadian embassy official).
A sample of an affidavit may read thus: "I, <translator's name>, of the town of <city/town name>, in the country of <country name> do solemnly declare: That I am fluent in the English and <your language> languages; that I have prepared a translation of the birth certificate of <your name>, attached hereto; that the attached document is a true and accurate translation from <your language> to English (or French); and that I make this solemn declaration believing it to be true as if made under oath."
Normally the translator and the official (lawyer, etc.) will date, sign and stamp their seals on the document to make it legal.