Old English. What is the origin “ht” suffix? Is it related to “th”?
Examples: bring & brought - strong & strength
I refer you to the online Etymology Dictionary. https://www.etymonline.com/word/thought
They explain it in terms of "thought"
thought (n.) Old English þoht, geþoht "process of thinking, a thought; compassion," from stem of þencan "to conceive of in the mind, consider" (see think). Cognate with the second element in German Gedächtnis "memory," Andacht "attention, devotion," Bedacht "consideration, deliberation."
Bammesberger ("English Etymology") explains that in Germanic -kt- generally shifted to -ht-, and a nasal before -ht- was lost. Proto-Germanic *thankija- added a suffix -t in the past tense. By the first pattern the Germanic form was *thanht-, by the second the Old English was þoht
GH
representing an earlier velar stop sound that velarized the nasal spelledNG
. You can see the same thing in German, where theCH
is pronounced: bringen, brachte, gebracht are the principal parts in German, and bring, brought, brought in English. Spelling is just technology and doesn't affect language.