Do I need to put a comma before every "because"? [closed]

There's a subtle difference in meaning with and without the comma. There is certainly no rule to put a comma before every "because", because the same sentence can be correct both with and without comma, with different meaning.

"This might be because another algorithm was chosen." The software was twice as fast as expected. We don't know exactly why this is yet, it might have to do with data that is easier to handle than expected, but it also might be due to a different choice of algorithm.

"This might be, because another algorithm was chosen." There is a claim that the software is faster as expected. I haven't verified the claim so I can't say whether it is true or not, but it is a possibility, due to a different choice of algorithm, which might have improved the speed.

In the example mentioned “A minority of Romanians speak English because it was outlawed under Ceaucescu”, without comma it means "the reason why these people speak English is resistance against Ceaucescu's rule", with comma it means "the reason why the English speakers are a minority is fear of Ceaucescu's rule". Take “The majority of Swiss speak English because it is taught at school from an early age”. Without comma: "They learn English because it is taught at school, not because they are actually interested in the language". With comma "The reason why so many speak English is the school system".

In these cases, "because" with a comma tends to refer to everything before that comma. "Because" without a comma tends to refer to the last independent item before because. Except that lovely rule doesn't apply to the original example!

No, you don't need to put a comma before every instance of because.

In the context of your question, a comma is used to separate two independent clauses joined by a co-ordinating conjunction (and, but, for, or, nor, so, yet) which may be where your corrector is getting the idea that because too should have a comma.

Other uses for commas are to set off parenthetical clauses (The man, who was French, smiled), separate items of a series (one, two, three), separate contrasting elements (It was hot, but cloudy), or after an introductory clause (Being nervous, the boy hesitated).