Don't know if you are Orthodox, Thirumeni is the malayalam equivalent for Syendna or Vladyka as used by Orthodox in the Middle east and in the Russian tradition. It denotes respect to the High Priest, roughly equivalent to My Lord, and is considered to be a more affectionate expression than the formal Syriac Mor or Moran .
Its usage is relatively recent in Kerala, earlier when Kerala was divided into 3 kingdoms only the King of Travancore was addressed as Thirumeni. Out of respect for the King, Christians both Orthodox and Catholic did not address their Prelates as Thirumeni, referring to them as Pithav or Valiya Achen meaning Father or Senior Father. It was only when the kingdoms became irrelevant that the current usage started.
Logos does not have an exact equivalent in malayalam that carries the deep meanings the Greek word carries, it is usually rendered as Vachanam or Word.