Why was the Pahlavi script difficult to read precisely?

The Pahlavi script was notoriously difficult to read due to several structural and orthographic complexities:

• Use of Ideograms: A primary challenge was the custom of using Aramaic words as ideograms to represent Pahlavi words. For example, the Pahlavi word for "king" (shāh) was written using the Aramaic word for king (malka), which was then read as shāh. This practice extended to many common nouns, verbs, conjunctions, and pronouns, creating a significant barrier to reading.1
• Limited Alphabet: The Pahlavi alphabet was derived from the Aramaic alphabet but contained fewer letters than were necessary to represent the full range of sounds in the language. Consequently, many letters were forced to represent multiple sounds.12
• Positional Ambiguity: Because of the limited character set, the pronunciation of certain letters depended heavily on their placement within a word. For instance, a single letter might represent the sound /o/ if it appeared at the beginning of a word, but represent /r/ if it appeared elsewhere.2