Here's a breakdown of its possible origins:
* Shortening: It's a simple case of shortening a common phrase, similar to how "thanks" evolved from "thank you."
* Regional variation: "Ta" is particularly common in some regions of the UK, especially in informal settings.
* Informal speech: It is often used in informal situations, similar to how "cheers" or "thanks" are used.
While the exact origin is debated, the use of "ta" is likely a natural evolution of language, driven by the desire for brevity and informality.