tongue · noun /tʌŋ/
tongue
B1 C the large soft piece of flesh in the mouth which you can move and which you use for tasting, speaking, etc.
Dictionary example:
I burned my tongue on some soup last night.
Learner example:
My mouth became so dry that my tongue stuck to my palate. (First Certificate in English; B2; French)
mother tongue
B2 the first language that you learn when you are a child
Dictionary example:
Italian is my mother tongue but I started to learn English when I was six.
Learner example:
I can speak English and French fluently, added to my mother tongue, Japanese. (First Certificate in English; B2; Japanese)