Likewise the Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit himself intercedes for us with groanings too deep for words.
Romans 8:26 ESV

“The Spirit” and not just “spirit”. It refers back to the firstfruits of the Spirit in v23, so this is the Holy Spirit and not our own spirits or an attitude. "Too deep for words" seems like a poor translation. The Greek doesn't say anything about depth. The word seems to mean "without words".

The deep intercession isn’t referring to us speaking in tongues--since this isn’t our spirit, but God’s, and Paul says the groanings have no words--but to direct communications between the Holy Spirit and the Father.