Alfa, not Alpha
The official international form is Alfa. Removing “ph” makes the intended sound easier to recognize for speakers whose languages do not use “ph” to represent an F sound.
Juliett with two Ts
The official form is Juliett. The doubled final consonant helps guide speakers whose languages might otherwise treat a final single T differently or leave it silent.
Spelling is part of the standard
In casual conversation, people often write Alpha or Juliet. For study, aviation, radio work, and formal reference, Phonetic Ready teaches the international forms Alfa and Juliett.