Why is the suffix -tion pronounced shun?

The pronunciation of the suffix "-tion" as "shun" is a bit of a linguistic quirk and doesn't follow a strict rule. Here's a breakdown:

* Historical Origin: The "-tion" suffix comes from the Latin "-tio," which was originally pronounced with a "t" sound. Over time, the pronunciation shifted in English.

* Sound Change: In Middle English, a sound change called "metathesis" occurred, which involves the transposition of sounds within a word. This shifted the "t" sound in "-tion" to the beginning of the syllable, creating a "sh" sound.

* Evolution of the "-tion" Sound: The "-tion" suffix evolved from the Latin "-tio" through several stages:

* Latin: -tio (pronounced with a "t" sound)

* Old English: -tioun (pronounced with a "t" sound)

* Middle English: -cioun (pronounced with a "sh" sound due to metathesis)

* Modern English: -tion (pronounced "shun")

So, the "shun" pronunciation isn't about a simple rule but rather a historical sound change that occurred over centuries.

Here's an example:

* Latin: "actio" (action)

* Middle English: "accioun" (action)

* Modern English: "action" (pronounced "ak-shun")

It's important to remember: While "-tion" is commonly pronounced as "shun," there are some exceptions. For example, words like "nation" and "situation" are sometimes pronounced with a "t" sound, especially in some regional accents.