Riir is right. As far as additional features from different firmwares - not typically. Sometimes there is something that is carrier specific or that one of the carriers asked Samsung to add or remove (like in the US for the S5, most of the carriers disabled the Download Booster, for example) but generally they all have the same underlying features. The languages and region specific stuff is often controlled by CSC files. I believe if you are rooted, you can change the CSC files in your current TW set up to enable some of that stuff.
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