Always pronounce "Thank you" as "THENGK-yoo," never as "THAYNGK-yoo.".

Same for "Thanks" ("THENGKS," not "THAYNGKS").

And for "Thankful" ("THENGK-fahl," not "THAYNGK-fahl."

"Thanksgiving" is "THENGKS-giving," not "THAYNGKS-giving."