When Paul said, "I speak in tongues" was he referencing the languages he spoke (1 Cor. 14:18)?

First and foremost, it is essential to understand Paul's perspective on the "gift of tongues" in 1 Corinthians 12-14. Paul neither dismisses the gift nor give it unqualified approval. Instead, he evaluates it pastorally and theologically, emphasizing its proper use within the congregation. From the passages below, it becomes clear that Paul challenges those who speak in tongues without interpretation, since such speech is unintelligible to the congregation and therefore requires interpretation.

• 1 Corinthians 14:2-5: 2 For anyone who speaks in a tongue does not speak to people but to God. Indeed, no one understands them; they utter mysteries by the Spirit. 3 But the one who prophesies speaks to people for their strengthening, encouraging and comfort. 4 Anyone who speaks in a tongue edifies themselves, but the one who prophesies edifies the church. 5 I would like every one of you to speak in tongues, but I would rather have you prophesy. The one who prophesies is greater than the one who speaks in tongues, unless someone interprets, so that the church may be edified.
• 1 Corinthians 14:13: For this reason the one who speaks in a tongue should pray that they may interpret what they say.
• 1 Corinthians 14:26-28: 26 What then shall we say, brothers and sisters? When you come together, each of you has a hymn, or a word of instruction, a revelation, a tongue or an interpretation. Everything must be done so that the church may be built up. 27 If anyone speaks in a tongue, two—or at the most three—should speak, one at a time, and someone must interpret. 28 If there is no interpreter, the speaker should keep quiet in the church and speak to himself and to God.

Given these context, Paul's statement in 1 Corinthians 14:18 - "I thank God that I speak in tongues more than you all" - should be understood as a reference to real human languages. As a Jew and a Roman citizen, Paul was multilingual: he could speak Hebrew, Aramaic (the common language of Judea), Greek and likely Latin, especially in light of his deliberate appeal to Caesar.

By contrast, the Gentile believers in Corinth would have known Greek or Latin but not Aramaic and Hebrew, while many Jews in Corinth may not have known Latin, which was typically used by high-ranking Romans. In this light, Paul's statement in 1 Corinthians 14:18 is entirely plausible: he is referring to genuine languages capable of edifying the church, not to unintelligible or ecstatic utterances.

No. He was definitely referring to glossolalia. This is clear from the context:

1 Cor. 14

The one who speaks in a tongue should pray that they may interpret what they say. 14 For if I pray in a tongue, my spirit prays, but my mind is unfruitful. 15 So what shall I do? I will pray with my spirit, but I will also pray with my understanding; I will sing with my spirit, but I will also sing with my understanding... 18 I thank God that I speak in tongues more than all of you. 19 But in the church I would rather speak five intelligible words to instruct others than ten thousand words in a tongue.

Paul is concerned that because tongues-speaking is unintelligible, the church needs to exercise discipline in its use. He calls for a balanced approach and provides various guidelines about this in these chapters. He states that he himself has the gift of glossolalia and exercises it often, both in prayer and singing. His own approach is to take care not to get carried away in the spirit, but to sing and pray "with my understanding." People need instruction as well as spiritual experience, so he prefers "intelligible words." In saying "I thank God that I speak in tongues more than all of you," he is clearly NOT referring to having the ability to speak several languages fluently.

The type of glossolalia that Paul is referring to in 1 Cor 14:18 is not of an intelligible language, which Paul constantly associates with the mind (intellect, reason, sober consideration) throughout this portion (v13-15). But instead of a tongue with the Spirit, which is why he goes on to say in v19 that in the public setting, without the interpretation of tongues (1 Cor 14:27-28), that it is markedly 2000 times better to speak in an intelligible tongue rather than in an unintelligible tongue.

19 however, in the church I desire to speak five words with my mind so that I may instruct others also, rather than ten thousand words in a tongue.

The OP asks:

Was Paul saying he spoke more languages that they did?

In my view, for Paul to boast (or factually state) here to the Corinth church about intelligible languages, would then stand contrary to his own later (few months?) admission of inferior oratorical abilities (2 Cor 11:6). Something, that a sect of the Corinthians even contemptuously rejected him for (2 Cor 10:10).

What did Paul mean that he spoke in tongues more than all of you?

The OP asks a good question here, since Paul is clearly referring to a tongues spoken in private, whether intelligible or unintelligible. So what yard stick does Paul use here to make this evidential statement? The purpose of private praying, thanking, singing of tongues, I find, is threefold:

1. Self-edification

1 Corinthians 14:4

One who speaks in a tongue edifies himself;...

Edification (Oikodomeo) can be understood as:

• Unshakable foundations revealed through faithfulness in tribulations (the parable of wise and foolish builders (Matthew 7:24-27, Luke 6:46-49 & Jude 20)) - Seen in Paul's undeterred faithfulness through afflictions many (2 Corinthians 11:23-28, Galatians 4:12-15)
• For discipleship entered through personal sacrifices as stated in the discipleship clauses (Luke 14:25-33) - Seen in Paul's divine call (Acts 9:15-16), Paul's attestations to it (Philippians 3:7-8, 4:11-13) and recorded in Paul's farewell to Ephesus in Acts 20:17-38
• To persevere through spiritual warfare (Ephesians 6:10-18) - Resisting the torment of the messenger of Satan (2 Corinthians 12:7-10, Satan's hindrance (1 Thessalonians 2:17-18), even battle with sin is spiritual on account of the Law being spiritual (Romans 7:14-20)

2. Intercession (personal and corporate)

Romans 8:26-27

26 In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words; 27 and He who searches the hearts knows what the mind of the Spirit is, because He intercedes for the saints according to the will of God.

We need the Spirit's help in all our intercessions for ourselves and others, because it is our inherent weakness (to understand a thing) to pray in the right way. Paul makes 11 mentions of prayer (or thanksgiving) for the church and individuals (Rom 1:9-10, 1 Cor 1:4, 2 Cor 13:7, Eph 1:16, 3:14-16, Phil 1:3-4, Col 1:3, 9, 1 Thess 1:2, 2 Thess 1:11, 2 Tim 1:3, Phil 4). Only twice, does he not use words that imply either constant or incessant prayers for his recipients (2 Cor 13:7, Eph 1:16). Similar language that Paul uses in Ephesians 6:18 when encouraging the believers to pray always in the Spirit. Paul, I opine, prayed in tongues constantly and therefore received an abundance of revelations to this end. And therefore he never ran out of prayer points neither was he stuck when making intercessions, since he had understanding of God's will for each believer and for the church as a larger entity.

3. Greatness of revelations

Revelations were and must continue be the bedrock of the Gospel message (Gal 1:11-12), as it was for even the well-versed apostle Paul. In Ephesians 3:1-13 as Paul affirms his divine calling in Christ to the church at Ephesus, he writes in v3 that by revelation there was made known to me the mystery, as I wrote before in brief. Probably, in earlier reference to Ephesians 1:9 where he mentions the mystery of God's will (emphasis own):

He made known to us the mystery of His will, according to His kind intention which He purposed in Him

And continues on in Ephesians 3:4 stating, By referring to this, when you read you can understand my insight into the mystery of Christ,.. Paul's insight (or understanding) came through revelation in the Spirit as he goes on to say in v5 ..which in other generations was not made known to the sons of men, as it has now been revealed to His holy apostles and prophets in the Spirit; Now having written nearly half of the new testament books, it is no mystery that Paul had an abundance of revelations, as he himself attests to (2 Cor 12:7).

Because of the surpassing greatness of the revelations,..

The apostle Peter notes in 2 Peter 1:20 that, But know this first of all, that no prophecy of Scripture is a matter of one’s own interpretation, but a move of the Spirt as the next verse goes on to say. With this chain of logic, I conclude that Paul received revelations (or interpretation) when speaking in tongues, which is after all speaking mysteries in one's own spirit (1 Cor 14:2). And through this abundance of revelations he received, maybe Paul would confidently go on to state as he does in 1 Cor 14:18.

We get the first reference of tongues in Acts 2:4-6:

All of them were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them. Now there were staying in Jerusalem God-fearing Jews from every nation under heaven. When they heard this sound, a crowd came together in bewilderment, because each one heard their own language being spoken. ".

Mind that the Apostles were only twelve in number and should have spoken in a great number of languages (Asia itself having hundreds of native languages), if they wanted Jews of every nation to understand what they said. Evidently, the Holy Spirit was at work, translating the gospel to "Parthians, Medes and Elamites; residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome ; Cretans and Arabs—"(Acts 2:9-11).

So, it is a 50:50 formula: the speaker speaks in language(s) other than his own native language and the Holy Spirit interprets the message to the audience in such a way that everyone hears in her/ his native language .Unfortunately, the Holy Spirit didn't work in all members of the audience at Pentecost :

Some, however, made fun of them and said, “They have had too much wine.” (Acts 2:13).

That could be one of the reasons why preachers are made by the Holy Spirit to speak in strange tongues: some understand; others don't , akin to the usage of parable by Jesus ( Mtt 13:13). ....................................................................St.Paul as a preacher, may have spoken in languages he hadn't learned or even understood by himself ; and his listeners heard him in languages over and above in number of what the Apostle spoke in. .................................................................. But, how do we understand 1 Cor 14:18 in the perspective of a critique ? First, let's catch Paul on the wrong foot. He is clear in 1 Cor 12:10 , that the Gift of Tongues comes from the Holy Spirit. However, the way he thanks God in 1 Cor 14 ( a general statement any layman without deeper knowledge of the Trinity would make in day-to-day conversations) implies that he is not referring to a Gift of the Holy Spirit.

Secondly, there is a fundamental difference between ' speaking a language' and ' speaking in it'. To quote Charles V,mutatis mutandis :" I speak French; but when I speak to God, I speak in Spanish...".

Granted that the English translators of Corinthians were aware of the difference , Paul meant speaking in languages other than his native language(s) and which served as his second-languages. ............................................................ Weighing both the options, the balance swings in favour of a scene in which Paul is not referring to The Holy Spirit's Gift of Tongues.