This variation in dialects and even writing systems can be another obstacle in meeting community needs.[28] Ebb and flow in a country's immigrant populations can also lead to significant variation in the abilities of heritage learners in a single classroom.[29] A study conducted by the National Heritage Language Resource Center (UCLA) shows that in the United States, heritage speakers' interest in their home language tends to wane as they enter school, but may rise again in the later teenage years, prompting the decision to study it in college.[28]