Which English letter combination should a first-grade teacher introduce first?

Introducing certain letter combinations to first graders involves considering their phonetic simplicity and frequency in English words. The combination "th" represents a common digraph where two letters create a unique sound, pronounced as /θ/ in "think" and /ð/ in "this." This sound is important for early readers, as it appears in numerous high-frequency words that they will encounter, making it essential for developing their reading and phonics skills.

In contrast, the other combinations, such as "ir," "kn," and "oi," either represent less common sounds or can be more complex for beginning readers to master. Thus, starting with "th" supports children in recognizing it in various contexts, contributing significantly to their fluency and comprehension as they progress in their reading abilities.