To 'speculate' is to engage in a course of reasoning often based on inconclusive evidence.
especular = to speculate
I can only speculate about the outcome of tomorrow's meeting.
Why do you speculate the obvious
It means that if we stop talking to each other, we will distrust each other.
I speculate that you are trying to get someone to do your homework.
I hesitate to speculate on that unique piece of jewelry.
Speculate why the poet chose these theme?
Yes. Speculate is a valid Scrabble word.
You shouldn't speculate why you haven't heard from them, call them and ask them.
The word speculate is a verb. The past tense form is speculated.
you can't