I have been reading some of the Upanishads in Bengali/English translation. Some of these translations also have the original Sanskrit (Bengali/Devanagari script).
I noticed that the English transliteration use the term "Brahman" instead of "Brahma" for ব্রহ্ম or ब्रह्म. Why has the extra "n" been added to "Brahma" and when did that usage start?