• Consider all cases when implementing word transformations:
  • Zero quantity may need special handling
  • Negative numbers
  • Decimal numbers
  • Language/locale specific rules
  • Irregular plurals (e.g., child -> children)
  • Words ending in y: only change to 'ies' if preceded by a consonant (e.g., "fly" -> "flies" but "day" -> "days", "key" -> "keys")
  • Words ending in s, ch, sh, x: add 'es'
  • Special suffixes (-es, -ies)

Simple implementations can lead to bugs. Prefer using established i18n/l10n libraries for production text transformations.

• Avoid quick, simple implementations for language-specific transformations
• Consider edge cases before implementing string manipulation functions
• Document assumptions and limitations in comments
• For text displayed to users, use i18n libraries rather than custom implementations
• Test with a variety of inputs including:
  • Empty strings
  • Special characters
  • Unicode/emoji
  • Very long strings
  • Different locales