There is no definitive collection of hymns. The church will always be adding new material for her praise. There is no special language of praise, but only ordinary speech used wisely and reverently. Nor is the church isolated from the culture in which she finds herself, so the musical form and style used in praise will vary from nation to nation and from age to age. The fact is that our personal tastes come in here - some older people like me grew up with an older musical style and prefer it and would like to stay with it.
Some young people are more comfortable with a modern style and want change.
Not all modern music is suitable for the worship of God. It isn't simply a matter of taste - much modern music is, in part, a product of the whole culture of a society which is increasingly godless and debased. Some music is simply difficult for congregations to sing. The Lord Jesus Christ has given leaders and pastors to the church, and we must expect them to act in this matter with integrity and sensitivity and a real concern for the glory of God. Perhaps one further point is worth making here.