Correct spelling


Correct spelling, explanation: this adverb is created from adjective total. To create an adverb from an adjective we add suffix -ly. The adjective total ends with consonant l, so it will double, as the suffix begins with l – we receive the word totally. It happens with other adverbs as well (beautifully, fully etc.). Therefore totally is the correct form, and totaly is incorrect.

Definition of totally:
adverb, in a total matter, fully; also colloquially: obviously
I totally do not understand this maths problem.
If I were you I would totally take this job!

Incorrect spelling


Incorrect spelling, explanation: totaly is a wrong spelling, because adjective total, with which we create the adverb, ends with l. When we add to it the suffix -ly (usual suffix for adverbs), we receive double l word: totally. There is no need to skip it as it is fully pronounceable. Therefore totally is the correct spelling.