Another way of saying what DY said is it there is a Havara Petucha before a BeGeD KeFeT, then the BeGeD KeFeT has no dagesh.
What is an Havar Petucha? It is when the last syllable ends with a vowel sound. At the end of a word this is usually with the letters of Yud Alef Heh and Vav, which are called together Yaihu.
If there is a cantillation that is a stop (like etnachta, revii, zakaif katone, pashta, etc) on the word that ends with Havara Petucha, then that cantillation stops the effect of the Havara Petucha. For example, Eleh Tolados Noach, not Eleh Solados Noach.
Also a Mapik Heh is considered a consonant.