I have to admit that, though I am familiar with 'especially' as an adverb, I haven't ever heard 'especial' except when spoken by a foreigner whose native languages pronounces the initial 'S' on words as 'ES' (such as in Spanish). That said, I confirmed in the dictionary that it is a valid, though uncommon, English language adjective synonymous with 'special'; therefore, I recommend that you use use 'special' as an adjective, and 'especially' as an adverb.

especial - extra special. for ex - these tradition are of especial interest of feminist.

both have alomost same meaning ,while the other word especial is also an English word which means better or greater than usual.

but "especial" is seldom used, though "especially" is