Uttering the intention out loud for salaat al-Taraaweeh and other prayers is bid’ah

During Ramadan we pray salat al-taraweeh, what is to be said in the
beginning of the prayer. for example nawatu asalee lillah al atheem fe
ta'at rubee al kareem rika'tein sinit........
Praise be to Allaah
Uttering the intention outloud when one is going topray is bid'ah (an
innovation), whether that is for Taraaweeh prayers or any other
prayer.
Ibn al-Qayyim said in Zaadal-Ma'aad (1/201):
When the Prophet (peace and blessings of Allaah be upon him) stood up
to pray, he would say: "Allaahu akbar," and he did not say anything
before that, or utter the intention (niyyah) out loud at all. He did
not say, "I am going to pray such-and-such a prayer, facing the
qiblah, four rak'ahs, as an imam or following an imam." And he did not
say "ada'an (ontime)" or "qadaa'an (making up a missed prayer)" or
"fard al-waqt (the obligatory prayer of this time)." These are all
bid'ahs which were not narrated by any scholar with any isnaad, be it
saheeh, da'eef, musnad ormursal … Neither was thisnarrated from any of
the Prophet's companions, and none of the Taabi'eenor the four imams
described it as mustahabb.
See also question no. 13337
So the Muslim should have the intention of praying Taraaweeh in his
heart only, and not utter anything out loud.
And Allaah knows best.