So long as vs. "as long as"?

Question

Which phrase is more formal — "so long as" or "as long as"?Example:> - So long as Google Voice allows free long distance in North America, I will use it.- As long as Google Voice allows free long distance in North America, I will use it.I'm leaning toward 'as long as' but I have no justification.

Answer 1

"SO long as" is a more slang, or colloquial, version of "AS long as". The true and formal way to say the conditional here is "as long as".

Answer 2

Though similar, the two phrases can have different meanings. "As long as" is a synonym for "until" while "so long as is a synonym for "while".

"As long as" would be the preferred use, depending on the meaning of the sentence. For example: "As long as I he needs me, I know where I will be".

"So long as" would be used for more informal conversations "So long as you're getting up, would you get me a coffee, too".

This is one of those phrases where repeated use has brought acceptance, so a sentence "So long as I have lived here, we have had dogs" is now acceptable, but, but not good grammar.