Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The tongue in a dream is its owner's interpreter, the manager of his affairs, and his argument. A long tongue indicates eloquence, talkativeness, and victory in disputes. The cutting off of the tongue indicates the invalidation of an argument or the death of an interpreter.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The tongue indicates authority. Whoever sees hair on his tongue, it is an increase in knowledge and poetry. Whoever sees that he has two tongues is blessed with double the knowledge and argument.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The tongue is interpreted as a son, a servant, or a consultant. Its being tied indicates poverty, incapacity, and corruption in religion. A tied tongue (in a knot) indicates eloquence and rhetoric.