Text: A Letter Is a Number in a Table
This very sentence, on your screen, is numbers in cells — tier 1 said so and proved it. Today we open the machinery: WHICH numbers, by WHAT table, and why the story has — unavoidably — two storeys. At the end, the famous gibberish of wrong-alphabet text (кракозябры have haunted every reader of Cyrillic email) stops being folklore and becomes a theorem you already proved two tiers ago.
Storey one: the character table
Text enters the machine by the oldest agreement in this course: a correspondence table pairing characters with numbers — the codebook of tier 1, now with a proper name. Historically there were many tables, and the early ones shared one design: one character = one cell's worth (one byte). Tidy, fast — and small: a one-byte table holds a couple hundred characters. Enough for one alphabet plus digits and punctuation; NOT enough for the world — so every language region minted its own table, the same numbers meaning different letters across borders. The stage for gibberish was built decades in advance.
The modern resolution is a single worldwide table — Unicode (the name will meet you everywhere) — with a number for every character of every script: Latin, Cyrillic, Arabic, Chinese, and far beyond. One table, one meaning per number, planet-wide. And immediately, a machine-sized problem: with more than a hundred thousand characters, a character's number may not fit one cell. The finite cell strikes again — and forces a second storey.