The most commonly used language tests for 8th-grade students in the United States are the SAT, ACT, and AP exams. These standardized tests assess a range of language skills, including reading comprehension, writing, and grammar. The SAT and ACT are primarily used for college admissions, while the AP exams are designed to provide college-level coursework and credit.

The SAT (Scholastic Assessment Test) evaluates critical reading, writing, and math skills, with a focus on language arts. The ACT (American College Testing) assesses English, mathematics, reading, and science reasoning. Both tests include questions that require students to analyze and interpret written text, demonstrating their understanding of language and its nuances.

The AP (Advanced Placement) exams in English Language and Composition and English Literature and Composition are specifically designed to measure students' ability to read, analyze, and write about complex texts. These exams are rigorous and are typically taken by students who have completed advanced English courses in high school.

Data from the College Board, which administers the SAT and AP exams, shows that in 2020, over 1.7 million students took the SAT, and over 2.8 million took the AP exams. The ACT, administered by ACT, Inc., reported that in 2020, approximately 1.9 million students took the ACT. These numbers highlight the widespread use of these tests in the United States for evaluating 8th-grade students' language proficiency.

The choice of language test for 8th-grade students depends on their educational goals and the requirements of their schools. For those aiming for college, the SAT and ACT are essential, as they are widely accepted by colleges and universities. The AP exams, on the other hand, are beneficial for students who wish to challenge themselves and potentially earn college credit.

In conclusion, the SAT, ACT, and AP exams are the primary language tests for 8th-grade students in the United States. They are designed to assess a range of language skills and are widely recognized for college admissions and advanced coursework. The choice of test should align with the student's educational goals and the expectations of their school.