specialize vs spell out

specialize and spell out both are verbs.

Word	Noun	Adjective	Verb	Adverb
specialize	No	No	Yes	No
spell out	No	No	Yes	No

As verbs, spell out is a hyponym of specialize; that is, spell out is a word with a more specific, narrower meaning than specialize:

specialize (verb)	spell out (verb)
become more focused on an area of activity or field of study	make explicit; specify in detail
suit to a special purpose	orally recite the letters of or give the spelling of
evolve so as to lead to a new species or develop in a way most suited to the environment	spell fully and without abbreviating
be specific about
devote oneself to a special area of work