Assalamoalaikum, i have injured my mouth and am unable to speak for a few days, how should i perform my salat during this period?
Allah the almighty said:
And when you have completed the prayer, remember Allah standing, sitting, or [lying] on your sides. But when you become secure, re-establish [regular] prayer. Indeed, prayer has been decreed upon the believers a decree of specified times. (4:103)
this verse tell you that you need to pray once the prayer time has began, it tells you that if you cannot pray the usual why you may pray while sitting or lying on your sides, so there's no excuse for praying except you are female and having your menses or childbirth bleeding ...
So there's basically no excuse at all for leaving the prayer, as Allah also says:
So fear Allah as much as you are able ...(64:16)
It also shows that in case you are not able to do something which is ordered as it should you may have a relief or an easier way to do it (for example if you are not able to stand you may sit, if you are not able to sit you may lay down, if you can't move at all than you may say the prayers in your mind or your heart). If you are female being injured at the mouth or tongue shouldn't bother you except if tongue movements would hurt or harm you as praying in a loud voice is not prescribed for them in any prayer. Allah also told us:
... and do not throw [yourselves] with your [own] hands into destruction [by refraining]. ... (2:195)
So we shouldn't do something that harm ourselves and therefore we must pray in a manner that doesn't harm ourselves, if you may get hurt by moving your tongue than say the prayers and recitations in your heart, if you are able to move your tongue then say them as you are asked, if raising your voice hurts don't do it. If it hurts you if rinsing your mouth in wudu' hurts or harms you don't do it (in this case it is even only a sunnah, so not doing it is allowed and not a reason to invalidate your ablution). Therefore if you are not able to move your tongue or not able to recite you may pray the prayer of a deaf or dumb: Normal movements , but without moving the tongue this is the view of the majority, the shafi'is require moving the tongue (but as explained above you may have a legal excuse for not doing it) if you are able to read either Arabic, Indonesian or Urdu you may refer to fatwa islamqa #213606. As you may have an excuse you don't need to perform sujud as-sahw (the prostration of forgetfulness).
So pray in the right manner that ease you without "stretching the permission" too much nor harming yourself and seek a middle way!