A verse and its Tafsir.
Allah the Exalted says:
"Allah presents the example of two men: one of them is dumb [abkam],"
The abkam is a person who was born mute.
Its plural form is bukm.
The Exalted says:
"Deaf, dumb [bukm],"
Thus, every abkam is mute.
But not every mute person is an abkam.
For whoever was able to speak,
And then lost the ability to do so,
Is considered mute, not abkam.
The text between the brackets,
Is from the vocabulary of the Qur'an,
By al-Raghib al-Isfahani.