Hey Homer
The book of Ephesians doesn't specifically mention speaking in tongues. However, some of the first believers there did.
(NKJV) Acts 19:1 And it happened, while Apollos was at Corinth, that Paul, having passed through the upper regions, came to Ephesus. And finding some disciples 2 he said to them, "Did you receive the Holy Spirit when you believed?" So they said to him, "We have not so much as heard whether there is a Holy Spirit." 3 And he said to them, "Into what then were you baptized?" So they said, "Into John's baptism." 4 Then Paul said, "John indeed baptized with a baptism of repentance, saying to the people that they should believe on Him who would come after him, that is, on Christ Jesus." 5 When they heard [this,] they were baptized in the name of the Lord Jesus. 6 And when Paul had laid hands on them, the Holy Spirit came upon them, and they spoke with tongues and prophesied.
We have no reason to think the Ephesians stopped speaking in tongues. And since Paul spent two years in Ephesus in the school of Tyrannus (Acts 19:10), he could have conceivably covered all of the teachings about the gifts of the Spirit which he wrote about in 1 Cor 12-14 while in residence there. We don't know this happened, but I see it as possible, if not likely.
You wrote:I do not think a case can be made for "praying in the Spirit" and "praying in tongues" being the same thing. Consider what Paul wrote:
Ephesians 6:18 (New King James Version)
18. praying always with all prayer and supplication in the Spirit, being watchful to this end with all perseverance and supplication for all the saints—
Watchful here is agrupneo meaning "intent on a thing, alert, perceptive" which hardly fits prayer where you do not understand what you are saying. How would you know you were praying for anyone?
I believe "praying in the Spirit" and/or "praying in the spirit" can be: 1) without words (per Sam's Romans, above), 2) in your native language, and, 3) in tongues.
If I'm praying in tongues for a specific person, persons, or a thing, I know what or who I have in mind. I just don't know exactly what my petitions are, other than for whom or what.
Praying in tongues is similar to groanings. If someone or something is on my mind or in my heart, I know the Spirit is interceding through me. I usually have a general idea of what is being prayed, especially if someone or something is weighing heavily on my heart.
At other times, I simply know that I'm praying (which can include praising) according to the will of God.
Not really into debating about this, just wanted to give (poor) TK a break!
(Hi TK, GBU Bro)!
Take care!