In most parts of Yorkshire and other parts of northern England, the slang word “ta” (pronounced “tar”) is used to mean “thank you”.
The word is simply substituted for “thank you” or “thanks”, so for example:
“Here’s that money I owe you.”
“Ta very much.”
From what I can gather from the mighty internetz, this is likely due to the large Scandinavian influence on the English language, particularly in the north. Consider that for thanks/thank you:
I believe that in those languages, the “k” sound is soft (more of a “g”), or even dropped. In Danish, the word is pronounced, “targ”, which is very similar to the pronunciation of “ta”.