For instance, we read the name in the English as Ahab, but the Strong's pronunciation is akh-awb' So in this case, the k sound is missing. Why are certain sounds missing if they are known?
Example:
22 And of them shall be taken up a curse by all the captivity of Judah which are in Babylon, saying, The Lord make thee like Zedekiah and like Ahab, whom the king of Babylon roasted in the fire (Jeremiah 21:22, KJV)
When translating names, a translator has, broadly speaking, 3 options:
Transliterate the name: spell out the sounds, as nearly as possible, in the target language. "Habakkuk" is an example of this translation practice going from Hebrew into English.
Translate the meaning of the name: whatever the name means, use the words in the target language that mean the same thing. The Latin "Petrus" (in English, "Peter") is an example of this translation practice. It means "rock", and in the New Testament is used to refer to the Simon called Cephas (e.g. 1 Cor 1:12) & Petros (e.g. Matthew 16:18). Cephas, Petros, and Petrus are all translations of an original name (Selah in Hebrew or Keifa in Aramaic) meaning rock.
Use an already accepted equivalent name in the target language. Some names are common enough to have existing equivalents in many languages (e.g. the name "David", which has been widely used for millennia, exists in some form in all Western languages and plenty of Eastern languages as well).
Translation is not an exact science, and all 3 options above are regularly used, at the discretion & judgement of the translator.
The process--and the potential to lose phonemes--becomes more complex when a name gets translated from one language to another via a 3rd-language intermediary. "Esaias" in some English translations of Matthew 3:3 is an example where a name was translated from Hebrew to Greek to English, and is thus rendered differently than the more common rendering, Isaiah, which skipped the Greek intermediary.