True about the functions of mylohyoid is:
Functions of mylohyoid are:

Elevates the hyoid bone during swallowing.
Elevates the tongue during speaking.
Forms ﬂoor of the mouth.
Separates submandibular space below from the sublingual space above (but they communicate around posterior border of mylohyoid).
Because the attachment of mylohyoid (the mylohyoid line) becomes more superior towards the posterior of the mandible, posterior infected teeth are more likely to drain into the submandibular space, and infected anterior teeth are more likely to drain into the sublingual space, since the apices of the teeth are more likely to be below and above the mylohyoid line respectively.
Elevates the hyoid bone during swallowing
Elevates the tongue during speaking
Forms floor of the mouth
All of the above