Simplify the following text for a Grade 12 native English-speaking person.
Original: Takalik Abaj was linked to long-distance Maya trade routes that shifted over time but allowed the city to participate in a trade network that included the Guatemalan highlands and the Pacific coastal plain from Mexico to El Salvador .
Simplified: Takalik Abaj was linked to long-distance Maya trade routes that let the city take part in a trade network that included the Guatemalan highlands and the Pacific coastal plain from Mexico to El Salvador .