# TR Agglutination Pitfalls: Suffix Tokenization + İ/I/ı/i Casefold Bug

> Source: https://sukruyusufkaya.com/en/learn/fine-tuning-cookbook/ftc-tr-agglutination-pitfalls
> Updated: 2026-05-14T14:42:56.751Z
> Category: Fine-Tuning Cookbook (Model-by-Model)
> Module: Part IX — Turkish-First & Localization Engineering
**TLDR:** Turkish is agglutinative — suffixes attached. Tokenizers often err on 'evlerimizdekiler'. İ/I/ı/i casefold bug, apostrophe normalize (TR vs ASCII), UTF-8 NFC vs NFD inconsistency. Cookbook's 'silent killer' bug list for TR engineers.