Edit: I already know that niyyah should not be uttered but should be made within the heart. My question is something else.
Should the niyyah for the salah be specific? For example people make up certain niyyah for the fard salah like "I am going to pray 4 rakat's of Asr, behind the imam, facing the Qibla..." and what not. Can the niyyah be just that "I am praying Asr salah"? I know that niyyah shouldn't be uttered and if I even leave the house to goto the masjid for praying Asr, that's my niyyah. Also, what about salah other than fard? Salah of Friday, eid, taraweeh etc. What should be the niyyah for these prayers. Thanks.