- In general, I like eating cheese.
- Generally, I like eating cheese.
It is a bit of a trick question, as they essentially have the same meaning, but they are different sentence components, and cannot always be used the same way.
Generally is an adverb, meaning usually or for the most part. For example “I generally get up at 8am.” (usually), or “This is a generally (mostly) popular song.” As it is an adverb of frequency, it can have different positions in a sentence / clause. It usually comes before the main verb, though it may also come after some verbs.
- They generally like to eat hotdogs.
- They play generally well.
It can also come at the start of the clause to add emphasis, and is rarely found at the end of a clause.
For more information on how word order rules affect adverbs like this, please download and read my guide to Word Order in English Sentences.
In general is an idiom, meaning generally. The two words (in + general) must come together to have this meaning (and you cannot put a word between in and general). Though it has the same adverb meaning as generally, it cannot be used as flexibly. It almost always comes at the start of a sentence, adding emphasis, or rather acting like an introduction. It should not come before a verb, though it can come after a verb, in commas:
- In general, the lesson was difficult.
- The lesson was, in general, difficult.
The second use is less common, and adds emphasis to in general.
Placing either in general or generally at the end of a sentence makes the idea sound uncertain, or more hesitant / tentative.
- I like this band, generally.
Note: you should never combine these two expressions. It is always in general or generally – do not say in generally!