Theory of phonetics

[м]
The front of the tongue is raised towards the hard palate, thus palatalizing the sound.

[n] Is articulated with the tongue tip touching the alveolar ridge, forming a complete obstruction to the air flow through the mouth cavity. The soft palate is lowered. The air passes through the nasal cavity. The vocal cords are drawn near together and vibrate.

[н] The blade of the tongue is pressed against the upper teeth, the tip being passive and lowered, thus palatalizing the sound.

[N] Is articulated with the back of the tongue raised and touching the soft palate, thus forming a complete obstruction to the air flow through the mouth cavity. The soft palate is lowered and the air passes out through the nasal cavity. The vocal cords are drawn near together and vibrate. [N] occurs at the end of a word or syllable. In order to avoid mispronouncing of this sound we are to prevent the tip of blade of the tongue from touching the upper teeth or alveolar ridge.

There is no counterpart in Russian. Keep the tip of the tongue pressed against the base of the lower teeth.

Constrictive

[f, v] Are articulated with the lower lip raised to the edge of the upper teeth, forming a flat narrowing. The air passes through it with friction. They are more intensive than the Russian counterparts.	[ф, в] The upper teeth are slightly pressed against the inner part of the lower lip.