Drink/Drank, Sink/Sank, Think/... thank?
English thank and think are cognate and come from the same Proto-Germanic root:
- Proto-Germanic: þank- = thought, gratitude, mental consideration
-
Old English:
- þencan = to think
- þanc = thought, goodwill, gratitude
Originally, “thanks” was essentially “good thoughts” or “favourable remembrance”.
So when you thanked someone, the underlying idea was roughly:
“I will think well of you”
or
“I hold your deed in grateful thought”
My intuition:
“I recognise you thought of me”
And so, the vowel alternation is related to the same Germanic ablaut patterns seen in:
- sing / sang
- drink / drank
- think / thought
Though thank is not literally the past tense of think, they are historically sibling forms produced by the same root-and-vowel-change system in Proto-Indo-European and Proto-Germanic.
Related words:
- German Dank = thanks
- German denken = think
- Dutch danken / denken
So the cognitive link between thought and gratitude is ancient and deeply embedded in the Germanic languages.