Sentence:  I was born in Kenya, and so was my mother. This makes me a Kenya citizen. My childhood and boyhood were in idyllic coungryside in Singida, Tanzania near Arusha. With beautiful lakes, bewitching butterflies, endless plains running for the horizon and people with the sweetness and suaveness of the Swahili. This makes Swahili, the main language of Tanzania, my <WSD>father tongue</WSD> and me a Swahili boy. 
Meaning of the word marked with <WSD> tags:  A second language that one speaks fluently.