3.5 Sound-Change Rules

Listen for the condition

A sound-change rule links a sound change to an environment. The environment might be the next vowel, the previous consonant, the beginning of a word, the end of a word, or the stressed syllable. For aptitude practice, the important question is not just what changed. It is when the change happens.

Use the compare-state-test method. Compare several examples. State the rule in plain language. Test the rule on a new item. For instance, in an original practice-style system, n might become m before p: san-pa becomes sam-pa, while san-ta stays san-ta. The rule is not n always becomes m. The rule is n changes before p.

A condition statement should include:

• The sound that changes.
• The environment that triggers the change.
• At least one example where the sound does not change.

Position rules are common in training because they are easy to construct. A final vowel might drop at the end of a phrase. An initial k might become g between vowels. A stressed vowel might lengthen. These are not official DLAB rules. They are examples of the kind of conditional listening that helps with unfamiliar language-like material.

Avoid overgeneralizing from one example. If you hear lom become lon once, you do not yet know whether m changes to n, whether final sounds change, or whether that single word is irregular inside the drill. Wait for a second example. Good rule extraction needs repetition. One example suggests; repeated examples confirm.

State rules in small words. Use before, after, at start, at end, when stressed, and when followed by. A rule such as t becomes d between vowels is easier to apply than a vague memory that the word sounded softer. The more exact condition protects you from answer choices that contain the right sound in the wrong place.

Sound-change rules often interact with stress. A practice-style system might pronounce a vowel long only when it is stressed. If you ignore stress, the vowel pattern appears random. If you mark stress first, the rule becomes predictable. This is why audio practice should combine stress, rhythm, and phonetic discrimination rather than training them as isolated tricks.

Check for no-change examples too. They are not filler. They tell you where the condition does not apply. A rule is stronger when it explains both the changed items and the items that stay stable.

When answer choices are written, do not let spelling override the heard pattern. The item that looks closest may not preserve the rule. If the examples show that n changes only before p, then an answer with m before t is probably wrong even if it feels similar. Apply the condition, not the general impression.

Review by writing the failed condition. Instead of writing missed sound change, write changed n before t but rule required change before p. That note gives you a precise correction. Over time, your ear learns to ask for the environment automatically, which is the real value of sound-change practice.