In English there is the verb 'to be silent.' We have many verbs made up of more than one word. I don't think we English would ever say 'he quiets' though to be complex about it if one is describing a process of becoming quieter, and eventually perhaps but not necessarily silent, one could say 'he quietens' or 'he quietens down.' however, that is not the same as saying 'he is silent.' Quiet indicates a low volume; silent no volume, no sound.You can also remain silent, as the police will tell you if you are arrested!
That sounds more like something "he" would do to someone or something though.
I don't think there's a single-word verb in English that we could use as a direct equivalent here, unfortunately. It's one of the joys of language learning, though - in picking up a new language, you may learn a great deal about the one you thought you knew...
Manuna, el tace is what he is doing in the present, if he keeps himself silent, then he is silent, but if he is silencing, then you have to say who he is silencing, so in English you would say he is silencing , but in Romanian you wouldn't use tace for that, you would say that he is making someone to he silent, you would say el face pe _ sa taca, with an a that has a u shaped hat in sa and the second a in taca
You are right that it is plain wrong but as PJKaiser indicates you can silence something (e.g. a gun with a silencer) or a person - it is a transitive verb requiring a direct object- something to do the action to - in almost all cases though if you worked in a factory where one of the roles was fitting silencers then perhaps the workers migh say he si silencing and omit the object because everyone knows what it is - I am being extreme here it would not be normal English grammar.
For this he has to first have been speaking - it describes the act of stopping speaking, not being silent afterwards, if we are getting colloquial we can say he keeps stum, shtum or schtum (germans will know where this comes from), he bites his tongue, he stays light lipped...
I am wondering whether LINISTI could come from latin LENIRE (Lenio 'lenis )meaning to quiet down, to calm, etc. and French LENIFIANT, Spanish LENITIVO, with the same meaning. In English you have LENIENT, LENIENCY, Silentios from Latin SILENTIUM, French SILENCIEUX, Spanish SILENCIOSO, English SILENT etc.
Actually linistit does mean calm (like not agitated) instead of quiet when it's used to talk about people or living things, usually, but if you use it to talk about things like a valley, o vale linistita, it means it is a quiet valley that doesn't uave much going on in it, or un lac linistit, means the lake is quiet and placid too, as there are no waves that ripple along the surface, at least that what comes to mind if it is linistit
Lng52, you linistit means a calm type of quiet, and it can be used to refer to just someone being calm rather than quiet, so if it's refering to a person, or another living thing, it means that the person is calm and is not / no langer agitated, whereas if it's refering to something like a valley, it means that it is quiet (o vale linistita
Nahuatl, I think he keeps IT quiet is a mistake because the phrase doesn't say what he is keeping quiet, and there is no context for us to assume what it could be The answer written for this section, at least now, is he is quiet, which I would say is a correct answer, but I think the answer you were showed is wrong