In high school Spanish class we conjugated a verb in a tense by listing the forms for 1st-person-singular, 2nd-person-singular, and so on through 3rd-person-plural.
Here I want to list verb, past, and past participle:
stink, stank, stunk
borrow, borrowed, borrowed
drink, drank, drunk
(I drink a glass of water, I drank a glass of water, I have drunk a glass of water. I think that's correct.)
sink, sank, sunk
I sink, I sank, I have sunk.
sing, sang, sung
think, thank, thunk
But no.
think, thought, thought
Think is an irregular verb. That's one more little thing that makes English more difficult.
Let's reinvent that verb:
think, thank, thunk
I think of it, I thank of it, I have thunk of it.
But the problem with that is: "thank" is already taken. It means to thank a person, as in "Thank you".
But there's a work-around for that. One can rely on auxiliary verbs to express the various verb forms:
I think of it. I did think of it. I have think of it. (Or, I have thinked of it.)
Or maybe this:
I think of it. I did think of it. I have thunk of it.
Years ago I took a little beginner's correspondence course in Esperanto. It was 10 lessons. It was given to me, and my work checked, by another dance partner of one of my dance partners (20 years ago when I round-danced). So I know a little about Esperanto. Esperanto is an invented language (as distinct from most languages which come into being naturally without a deliberate, thorough, logical design). One of the main characteristics of Esperanto is the regularity of its forms such as grammar, spellings, verb forms, and so on. It has very few exceptions. It has very few, if any, irregular verbs. I still have an old weatherbeaten Esperanto-English paperback dictionary he gave me, the pages all separated from the binding by now. Esperanto grammar is so simple that it's listed as "The Sixteen Rules of Esperanto Grammar" in the front of this dictionary. Verb forms are also simpler than in English. On page 30 of the dictionary it shows:
mi amas (I love), mi amis (I loved), but no pas participle on that page. All verbs have -as for present tense, and -is for past tense. Page 11 says to avoid compound tenses where possible. See, Esperanto makes an effort to keep things simple. However, participles in Esperanto do exist and they all end in "a". On page 10 I figure out that "I have loved" would be "Mi estas ama".
If English were regular, as Esperanto is regular, then instead of "think, thought, thought", or "think, thank, thunk", we might have something like this:
think, thinked, thinka
I think, I thinked, I have thinka
Or:
thinkas, thinkis, thinka
I thinkas, I thinkis, I have thinka.
