Is this the first time Alma heard the word of the Lord? Mosiah 26:15

Is this the first time Alma heard the word of the Lord? Mosiah 26:15

The rising generation is going astray, including Alma's own son Alma. So Alma the Elder prays to God, "pouring out his whole soul to God" and the voice of the Lord came to him saying, basically something like this:

[paragraph about blessing]
You're blessed Alma. The people who were baptized in the waters of Mormon are also blessed. You're blessed for your faith in the words of my servant Abinadi. And they're blessed for their faith in the words you preached to them. You're blessed for establishing a church among this people. And they will be blessed, too, and they will be my people. This people is blessed for being willing to bear my name. They will be called after my name, and they are my people. You are blessed for asking me about the transgressor.

[paragraph about who you are in my church]
You are my servant, and I covenant with you that you will have eternal life. You will serve me and go forward and gather my sheep. The people who hear my voice are my sheep, and you will receive him into the church, and I will receive them. My church is made of people who are baptized to repentance. Whoever you receive will believe in my name, and I will freely forgive them.

[explanation about why I will forgive]
I'll freely forgive them because I took upon myself the sins of the world. I'll freely forgive them because I created them. I'll freely forgive them because it's up to me to give people who believe a place near me.

[promises about forgiveness]
They are called in my name, and if they know me they will come to me and have a place near me eternally.

Some day in the future, a trumpet will call out and all the people who never knew me will come to me and stand before me. They will know that I am the Lord their God, their Redeemer, and they will know that they chose not to be redeemed. I will tell them that I never knew them and they will leave and go to everlasting fire prepared for the devil and his angels.

[how to deal with people who do not repent]
Whoever doesn't hear my voice should not be received into my church because I will not receive him in the end. [i.e. it's not the act of joining the church that brings salvation, it's conversion of the heart and actually coming to Christ that brings salvation]

So, Go. Judge the people who transgress against me according to the sins they commit. If they confess their sins to you and to me, and sincerely repent, you will forgive him, and I will forgive him.

[how to deal with people who repent]
I will forgive sins/wrongs against me as often as people repent.

And you will also forgive each others' wrongs against each other because the person who fails to forgive his brother for his wrongs when he says that he repents brings blame/wrong upon himself.

So, Go. Whoever will not repent will not be one of my people, and this is how you will do it from now on.

/endrevelation

Alma wrote down these words.

Answer:
From the first part of his words which say that he was blessed for his faith in Abinadi's words alone, it sure does sound like this was the first experience Alma had with hearing the voice of Jesus Christ in a revelation.