Is repeating words in mind necessary to some meditations in Theravada? Why or why not?

Question

According to Visuddhimagga, focusing on breath does't require repeating "inhalation, exhalation..." in mind (at least it seems that the book doesn't explicitly tell that) . However, the 10 Kasinas and the 10 foulness may need repetitive words in mind. For example:

"Anyone else should use that same kind of circle of luminosity just described, developing it as “luminosity, luminosity” or “light, light.”(Vm. The Remaining Kasinas.The Light Kasina)

I think that the principle of the 10 Kasinas is focusing on concepts of meaning. So maybe repeating the concepts of word isn't necessary.
Many modern experts also imply repeating words when meditating but give no further explanation.

Answer 1

I use mental verbalizations of the in-&-out breathing as to cut off [replacing] distracting thoughts should there be any.

He should develop...mindfulness of in-&-out breathing so as to cut off thinking. Meghiya Sutta Ud4.1

I assume that can be said in reference to this

When evil unskillful thoughts connected with desire, hate, and delusion arise in a bhikkhu through reflection on an adventitious object, he should, (in order to get rid of that), reflect on a different object which is connected with skill. Then the evil unskillful thoughts are eliminated; they disappear. By their elimination, the mind stands firm, settles down, becomes unified and concentrated, just within (his subject of meditation).

Like an experienced carpenter or carpenter's apprentice, striking hard at, pushing out, and getting rid of a coarse peg with a fine one, should the bhikkhu in order to get rid of the adventitious object, reflect on a different object which is connected with skill. Then the evil unskillful thoughts connected with desire, hate and delusion are eliminated; they disappear. By their elimination the mind stands firm, settles down, becomes unified and concentrated, just within (his subject of meditation). MN 20 Vitakkasanthana Sutta: The Removal of Distracting Thoughts

When developing perceptions of death, inconstancy, not-self, unattractiveness one has to contemplate reflecting on these things.

Sometime one will direct the mind to a theme connected with skill and withdraw from that when the mind has been gladdened or when the unwholesome perceptions have been stilled. Having withdrawn one stops thinking and remains mindful without thinking.