Special is a common adjective. Specially is its adverb form. Specially means "particularly, in a disintguishing manner, or for a particular purpose."
Especial is an uncommon adjective. Especially, its adverb form, is much more common. Especially means "exceptionally, in a noteworthy manner, or particularly."
Specially is used to mean for a particular purpose, this form of the adverb is the norm:
This shower gel is specially designed for people with sensitive skins.
This computer programme is specially for children with learning difficulties.
My father made this model aeroplane specially for me.
especially - particularly / above a
Especially should be used for emphasis, meaning particularly or above all:
I'm sorry. I thought that I had put example sentences on my previous post. Here you go:
Specially is used when showing a distinctive purpose:
-This program has specially designed macros for word processors.
-This shower gel is specially designed for people with sensitive skins.
-This computer programm is specially for children with learning difficulties.
-My father made this model airplane specially for me.
Especially is used when talking about a noteworthy performance and/or trying to emphasize something:
-He did especially well in All-Star Game.
-These butterflies are particularly noticeable in April and May, especially in these meadows.
-You'll enjoy playing tennis at our local club, especially on weekdays when it's not so busy.
Additionally, aside from meaning, form also plays a part in the confusion. Some speakers tend to drop the initial "e" on "especially" or tend to pronounce the "e" fairly weakly, which makes "especially" (i.e., particularly) homophonous with "specially" (i.e., specifically, exceptionally) and hard to pick out:
EX: These butterflies are particularly noticeable in April and May, specially; i.e., particularly) in these meadows.
EX: You'll enjoy playing tennis at our local club, specially;i.e., particularly on weekdays when it's not so busy.