What is "Seson Yish'echa"?
Rashi: It is Ru'ach ha'Kodesh, which left me. Radak - this is the Simchah of the Neshamah, and its salvation.
Sha'arei Teshuvah (1:42): Hashem's miracles and salvation should be frequent by me, and Ru'ach ha'Kodesh should be on me like before the sin.
Malbim: You will oversee me, and save me from mishaps.
What is "Ru'ach Nedivah"?
Radak: It is Ru'ach ha'Kodesh, which volunteers words of song and praise to Hashem.
Malbim: This correspond to "v'Ru'ach Kodshecha Al Tikach Mimeni" (verse 13). The Ru'ach should support me in ways of perfection.
What is the conjugation of "Tismecheni"?
Radak #1: It is feminine; the subject is Ru'ach. Rambam (Hilchos Teshuvah 6:4) - let my Ru'ach ha'Nedivah do its desire, and my sins should not prevent me from doing Teshuvah.
Radak #2: It is second person (addresses Hashem); support me b'Ru'ach (with a spirit) Nedivah.
