LESSON 2.8 · Lab · 90 min

The hidden cost of tokenization

The hidden cost of tokenization. Learn numbers, whitespace, multilingual text, special tokens, and compression and complete: Compare tokenization pathologies across Chinese, Englis

Learning objectives

  1. Explain what problem “The hidden cost of tokenization” solves without hiding behind terminology.
  2. Trace the variables and causal links across numbers, whitespace, multilingual text.
  3. Complete “Compare tokenization pathologies across Chinese, English, and Japanese” and judge the result with evidence rather than intuition.

Core concepts

numbers

numbers is part of the lesson’s causal model. State its inputs, outputs, invariants, and failure mode; then verify it with a hand-check or a minimal experiment before moving to an optimized implementation.

whitespace

whitespace is part of the lesson’s causal model. State its inputs, outputs, invariants, and failure mode; then verify it with a hand-check or a minimal experiment.

multilingual text

multilingual text is part of the lesson’s causal model. State its inputs, outputs, invariants, and failure mode; then verify it with a hand-check or a minimal experiment.

special tokens

special tokens is part of the lesson’s causal model. State its inputs, outputs, invariants, and failure mode; then verify it with a hand-check or a minimal experiment.

and compression

and compression is part of the lesson’s causal model. State its inputs, outputs, invariants, and failure mode; then verify it with a hand-check or a minimal experiment.

Build and verify

Compare tokenization pathologies across Chinese, English, and Japanese

  • Predict: write the expected output, trend, or failure before running code.
  • Build: implement only the minimum components needed to answer the question.
  • Verify: compare with a baseline or trusted implementation; save seeds, parameters, and raw outputs.
  • Transfer: change one shape, dataset, scale, or workload condition and explain whether the conclusion still holds.

Open the complete interactive lesson