I have heard an interpretation and interpreted in various scenarios--I have spoken the message in tongues and someone else has interpreted, I have interpreted when someone else spoke, and I have spoken in tongues and interpreted immediately. I have walked with the Lord for 16 years and believe I have heard approximately 30-40 gifts of tongues with interpretation during that time. I have been used probably no more than 7 or 8 times, but I have not kept track. I have not attended a church that is open to tongues with interpretation for many years and so the gift has been dormant.
Here is my description of it, which is by no means a definite standard, just how I would describe what I have witnessed/participated in:
1. I attended a church for years that had messages in tongues with interpretation. I eagerly desired the gift as a young Christian (probably 3 years in the Lord) and prayed that God would give me the gift.
2. I felt led by the Lord a couple of times to either give an interpretation or a message in tongues, but was not sure and did not step out in faith the first couple of times. Knowing the leading was there, and regretting that I did not step out in faith, caused me to want to be more obedient to God the next time (if there ever was going to be a next time).
3. When the opportunity to be obedient came up again, it felt like I was being compelled by the Holy Spirit to speak a message in tongues, much like we can feel compelled by the Holy Spirit to do or not do something. Our choice to obey is just that--a choice. I never once felt out of control or like I had to give the message that second. When a moment came in the service that was an obvious opportunity, and orderly, I stepped out in faith. I would like to add that many times I have seen a large congregation of 2000 go from loud praise of God with singing, praying, and clapping to almost pin drop silence when it was the right time for the message to come forth. My conclusion is that God can lead his people to create the opportunity for the message. Also, the internal witness of the Holy Spirit does feel different to me when I give a message versus interpreting one. Giving a message feels like an impelling from the Holy Spirit and like rivers or running water that the Holy Spirit desires to have flow out of me. Interpreting feels more like doing something by faith where I know very little, but I trust God to do the work through me.
4. When I have spoken the message in tongues, it did not sound like my usual language that I hear when I pray to God privately in tongues. The language sounded unique and one of a kind each time. It also did not sound repetitive as though 3 or 5 words were being spoken over and over again.
5. All but one of the times I have been present for an interpretation, or given an interpretation, was in a congregational setting inside a church. Amazingly, when in a congregational setting (in an auditorium of 300 or 2000) the voices of those I heard speak in tongues or give interpretations were magnified a lot so that they could be heard very clearly and loudly. When I spoke as part of tongues or interpretation, my voice was amazingly magnified, but it did not feel or sound like I was yelling. It just sounded like my voice really loud and strong.
6. After realizing that God uses me for the gift of interpretation, I am very vigilant when I hear a message given. If God is planning to use me for the interpretation, he gives me the first few words and I feel his leading that I should speak out in faith. The other words come as a flow that feels like it is in real time with the words usually coming out of my mouth without me judging them or turning them over in my mind. It feels like a continuous stepping out in faith. At some point, the words stop coming to me, and I stop speaking. Afterwards I feel full of worship and I want all glory to be given to God.
Usually, I can only remember part of the message because my focus is just on letting God have his way. I will say that oftentimes my flesh and the devil try to condemn me and make me question and doubt--especially with interpretations. I have some friends who are very devout and I have asked them their honest opinion because I would never want to give a false interpretation.
7. I believe that I have given the message and interpreted it immediately two times. After giving the message, I waited a few seconds and God gave me a few words to speak, so I spoke them in faith. I believe those two times it is likely that no one else present could or would interpret. It could definitely be the case that God wanted to use someone else to interpret, but they were not confident to step out in faith.
I have heard some amazing stories of people giving messages with interpretation, including one where the congregation present was from Assemblies of God worldwide and so many different languages were spoken. There was one message in tongues followed by many interpretations of the message in the different languages.
Also, a pastor I know was led by God to give an interpretation, "Humpty Dumpty sat on a wall, Humpty Dumpty had a great fall, all the kings horses and all the kings men, couldn't put Humpty back together again. You are here today and you feel like Humpty Dumpty, but God can put you back together again." He really didn't want to give the interpretation and was questioning God about whether he was really hearing from God. But God confirmed to him, so he gave the interpretation. Afterward, he spoke with an unbelieving couple who were visiting the church. The man had said to his wife that morning in church that he felt like Humpty Dumpty and no one could put him back together again. The man and his wife were born again that day. Praise GOD!!