English Translation
It becomes an ingrained habit.
Jisho.org says that 習い性 is pronounced ならいしょう, but then has the phrase 習い性となる with the reading ならいせいとなる. Is this true?
@cstuartroe
習い性になる is pronounced ならいせい. I recommend you to use Japanese-Japanese dictionaries such as goo辞書 sourced from 小学館‘s 大辞泉 and コトバンク.
As both of the JP-JP dictionaries explain, the sentence structure is 習い + 性になる(i.e. particle が is dropped from 習いが性になる. That’s a typical form of proverbs and axioms.) There is no 習い性 as a compound word like 凝り性 (pron. こりしょう; meaning: perfectionist). Therefore, 習い性になる isn’t pronounced ならいしょう.