Speaking in tongues?

[goodnews]

1 Corinthians 14:22 Wherefore tongues/languages are for a sign, NOT to them that believe, BUT to them that believe NOT: This first part of the verse explains that the deciples spoke to unbelievers purposely in their own tongue, as a sign in which they were to be believed, as the rest of the verse points out that prophecy only serves believers . How the deciples speaking to strangers in there own language became this "mumbo jumbo" amongst bretheren within a church, is beyond my grasp.