formulate vs speculate

formulate and speculate both are verbs.

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

As verbs, speculate is a hypernym of formulate; that is, speculate is a word with a broader meaning than formulate:

Other hypernyms of formulate include conjecture, hypothecate, hypothesise, hypothesize, suppose, theorise, theorize.

formulate (verb)	speculate (verb)
put into words or an expression	reflect deeply on a subject
elaborate, as of theories and hypotheses	to believe especially on uncertain or tentative grounds
come up with (an idea, plan, explanation, theory, or principle) after a mental effort	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
prepare according to a formula	invest at a risk