1Cr 14:39   ... forbid not to speak with tongues.

The Spiritual Gift known as "Tongues" is a gift of the Holy Spirit, and is distributed to some believers by the Holy Spirit according to His Will, not the will of man.   See 1 Corinthians 12 and 1 Corinthians 14. 

All of the disciples at Pentecost received the Gift of Tongues (Acts 2), and they spoke real, understandable languages of men that they had not learned.  Some believers hold that there is a different gift of Tongues which isn't a real language of men, but rather is a 'private prayer tongue'.  This is the common 'type' of tongues practiced today, and not actual 'unlearned', understandable languages of men.  1 Cr 14:2-4 could possibly be interpreted as a separate 'prayer language', but most scholars do not interpret the passage that way, and the 1 Cr 12 list of Spiritual Gifts does not separate "Tongues" into two different kinds.  Some interpret 1 Cr 13:1 "tongues of angels" as this private prayer tongue. 

In the early church, as narrated in the Book of Acts, many believers received the gift of tongues at the moment of salvation, while in at least one case some who had "repented" and who had received the "Baptism of John" did not receive the Holy Spirit until they were told about Christ himself, and as a testimony, they then spoke in tongues (Acts 19).  However, the gift is not directly specified as necessarily associated with salvation in New Testament books written later, and indeed is not mentioned at all other than to be regulated in 1 Cr 12 and 14.  

Some churches teach that receiving the "Baptism of the Holy Spirit" and the gift of tongues is subsequent to salvation, and is what empowers a believer for Christian service, however this is no where specifically limited in scripture.  Indeed, since Paul specified that if a person does not have the Holy Spirit then they do not belong to God (Rom 8:9), it is clear that a person must receive the Holy Spirit at the moment of salvation.  In fact, Paul further states that the Holy Spirit is the 'downpayment' ('earnest') of our spiritual inheritance (Eph 1:13, .  Some could possibly argue that 'receiving the Holy Spirit' at salvation is a separate event from the "Baptism of (or in) the Holy Spirit", but a scriptural reference to that distinction is lacking.

Do all Christians speak in Tongues?

1Cr 12:30 Have all the gifts of healing? do all speak with tongues? do all interpret?     Paul's rhetorical answer here is - No, not all speak in tongues.  The Greek grammatical sentence structure in this passage gives the rhetorical answer of 'no'.   Although 'Tongues' was declared in scripture as a valid gift of the Holy Spirit, not all Christians have this gift, nor are they encouraged to seek this gift; rather, they are encouraged to seek "the best gifts" 1Cr 12:31.  In fact, it is clear in 1 Cr 12 that in no case does every Christian receive the same specific gift, but they are distributed by the Holy Spirit to separate individuals to serve the Church for ministry.  ... do all speak with tongues? - No.

Does the "Baptism in the Holy Spirit" always result in the individual receiving the "Gift of Tongues"?

Although there are several narratives in the book of Acts where individuals spoke in tongues after receiving the Holy Spirit, the gift is not to be equated with "The Baptism of the Holy Spirit" (the Spirit of God).  Paul said later on that if anyone did not have the Holy Spirit (the spirit of Christ), then that person is not a true Christian  - does not belong to God.  Rom 8:9 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. 

Now, since Paul has already stated that not every Christian speaks in tongues, and he has also said that you have to have the Holy Spirit to be a true Christian, it follows that receiving the Holy Spirit does not always result in receiving the "Gift of Tongues".    A complete study of "Baptism" gives a better understanding of the biblical phrase "Baptism in the Holy Spirit".

Can there be abuses to speaking in tongues?

1Cr 14:23   If therefore the whole church be come together into one place, and all speak with tongues, and there come in [those that are] unlearned, or unbelievers, will they not say that ye are mad?

1Cr 14:40   Let all things be done decently and in order.

Since Tongues have caused trouble in the church, shouldn't that practice (gift) be rejected?

1Cr 14:39   Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues.

Here is another writer's point of view that I appreciate.   http://www.mslick.com/gifts.htm