Context: Older letters of the Russian alphabet include ⟨ѣ⟩, which merged to ⟨е⟩ (/je/ or /ʲe/); ⟨і⟩ and ⟨ѵ⟩, which both merged to ⟨и⟩ (/i/); ⟨ѳ⟩, which merged to ⟨ф⟩ (/f/); ⟨ѫ⟩, which merged to ⟨у⟩ (/u/); ⟨ѭ⟩, which merged to ⟨ю⟩ (/ju/ or /ʲu/); and ⟨ѧ/⟨ѩ⟩⟩, which later were graphically reshaped into ⟨я⟩ and merged phonetically to /ja/ or /ʲa/. While these older letters have been abandoned at one time or another, they may be used in this and related articles. The yers ⟨ъ⟩ and ⟨ь⟩ originally indicated the pronunciation of ultra-short or reduced /ŭ/, /ĭ/.

Question: What did the old letter ⟨ѣ⟩ become?
Answer: ⟨е⟩

Question: What did the old letters ⟨і⟩ and ⟨ѵ⟩ become?
Answer: ⟨и⟩

Question: What did the old letter ⟨ѳ⟩ become?
Answer: ⟨ф⟩

Question: What did the old letter ⟨ѫ⟩ become?
Answer: ⟨у⟩

Question: What did the old letter ⟨ѭ⟩ become?
Answer: ⟨ю⟩

Question: What  did the ja or a originally indicate the pronunciation of?
Answer: Unanswerable

Question: What did the r become?
Answer: Unanswerable

Question: What did the h become phonetically?
Answer: Unanswerable

Question: The ja or a indicated the pronunciation of a reduced what?
Answer: Unanswerable

Question: What was ja merged into?
Answer: Unanswerable