Semantic Typography

Number Separators

Decimal and grouping separators are locale-dependent symbols whose incorrect substitution can change numerical meaning.

Reviewed 2026-08-20Locale-dependent semantic conventionContext required
CategorySemantic Typography
Rule strengthLocale-dependent semantic convention
Locale applicabilityall
Avellio detectionSupported
Issue identifiersNUM_FORMAT
Correction authorityPreview/manual only; Avellio does not rewrite separators automatically.

Definition

A comma can be a grouping mark in one locale and a decimal mark in another. Typography must preserve the intended value and often follow the dominant pattern of the document or data source.

BAD vs GOOD

BAD
Mixed document

1,200.50 beside 1 200,50 without a documented locale change

GOOD
Explicit locale

EN US: 1,200.50 · FR: 1 200,50

Why it matters

Blind conversion can multiply or divide the apparent value by orders of magnitude.

Rule strength

Locale-dependent semantic convention. This is not an absolute linguistic law; locale, genre, content, and house style can change the correct decision.

Exceptions and editorial considerations

  • Scientific notation, software formats, financial systems, and imported datasets can prescribe fixed separators.
  • Latin American conventions vary by market.

How to fix it manually

  1. Confirm numeric meaning and source locale.
  2. Choose the correct grouping character and decimal symbol.
  3. Normalize like-for-like content, not every punctuation mark in the document.

Adobe InDesign guidance

Avoid generic period/comma replacement. Work from validated data patterns and preserve tabular alignment and non-breaking grouping.

How Avellio detects it

Avellio emits NUM_FORMAT for mixed separator conventions against the resolved locale and dominant document pattern.

Action safety

Preview/manual only; Avellio does not rewrite separators automatically.

Check this automatically in Adobe InDesign

Language and locale differences

EN USEN UKEN AUEN NZ

Comma grouping and decimal point are the Avellio profile model.

DEFRCZPLITESPTBR

Decimal comma is common; grouping may use dot, space, or locale-specific convention.

DE CHFR CHIT CHCH Mix

Swiss profiles recognize apostrophe-like grouping conventions.

Compare all published language and locale guides.

Authoritative references

  1. Avellio User Manual — Locale profile referenceAvellio product source
  2. Unicode CLDR — Number and currency patternsLocale data standard

Avellio references document product behavior. External standards and authorities support the general or locale-specific typographic guidance. Where traditions disagree, this page states the disagreement instead of manufacturing one universal rule.