The timeline for this entry shows the period during which this people were active (that is, through the later Third Age and into the Fourth). Rochír-rim as the form of their name appears to have been replaced relatively quickly by the more familiar Rohirrim, but we're given no specific indication of how long this process took. Indeed, it is conceivable that loremasters even at the end of the Third Age might still have been using the more precisely translated form Rochír-rim.

The ch sound in this name represents a 'back spirant', a hard sound as in Welsh or German bach, rather than the sound in English 'cheer'. This is formally a 'voiceless uvular fricative', a sound not generally used in English (though it does appear in some regional accents, notably that used in the city of Liverpool). This sound was as unfamiliar to the Gondorians as it is to most English-speakers, hence the adaptation of Rochír-rim to the more familiar (and more easily pronounceable) Rohirrim.