What is characterized by the pronunciation of each letter in the formation of a word?

The correct choice is characterized by the pronunciation of each letter in the formation of a word. This is identified as alphabetism, which involves taking an initialism and pronouncing each letter individually. For instance, the abbreviation “F.B.I.” is pronounced as "eff-bee-eye," where each letter is articulated separately. This method differs from acronyms, which are typically formed from the initial letters of a phrase and pronounced as a single word, such as "NASA."

Abbreviations, in a broader sense, can involve truncating words or phrases without necessarily focusing on the pronunciation of individual letters. Meanwhile, blending refers to the combination of parts of two or more words to create a new word, such as “smog” from “smoke” and “fog.” Thus, the unique feature of alphabetism is that it emphasizes the explicit pronunciation of individual letters, setting it apart from the other concepts listed.