speculate vs bethink

speculate and bethink both are verbs.

Word	Noun	Adjective	Verb	Adverb
speculate	No	No	Yes	No
bethink	No	No	Yes	No

As verbs, bethink is a hyponym of speculate; that is, bethink is a word with a more specific, narrower meaning than speculate:

Other hyponyms of speculate include premeditate, theologise, theologize, introspect, cogitate, question, wonder, puzzle, consider, study.

speculate (verb)	bethink (verb)
reflect deeply on a subject	consider or ponder something carefully
to believe especially on uncertain or tentative grounds	cause oneself to consider something
talk over conjecturally, or review in an idle or casual way and with an element of doubt or without sufficient reason to reach a conclusion
invest at a risk