Especially or Specially?
This is a horrible area of English - I'm so sorry! But generally these rules should help you.
With an adjective, they can both mean 'more than normal' but especially is much more common. For example:
This vocabulary isn't especially/specially difficult.
Use especially to mean 'particularly' (or 'more than other things'). It is usually used after a comma:
I love watching films, especially horror.
Use specially to mean 'for this particular purpose'. It is usually used with the preposition 'for', or with a passive verb structure:
I rented this horror film specially for Halloween.
These houses were specially built for small families.
Don't use especially or specially at the start of a sentence. We use in particular to link two sentences.
I love watching films. In particular, I really like horror films.
Choose the best word/expression to complete these sentences.
Another note: This area of English is very advanced, and lots of websites seem to disagree with each other. It can be a good idea to use corpus data (e.g. from the British National Corpus) which gives you examples of how people use vocabulary. Another way to see which expressions are more common (on the internet) is to use Google fight which is just fun!