How much freedom do freshmen have in choosing courses?
In their first semester of school, freshmen do not have any freedom in choosing their courses. Instead, all freshmen take the same four common curriculum modules. In the second semester of freshman year, this is amended to three common curriculum modules and one elective of their choosing (provided that the student is qualified to take it).
In terms of elective qualifications, many higher-level modules require students to have taken a lower-level module beforehand (often an introductory module). However, there are a lot of modules that allow students to skip the introductory course if they already have the necessary academic qualifications (like if they’ve already studied the subject at a sufficiently high level in high school). For these cases, you should email the professor in charge of the class to make arrangements. If you want to study a language, your level will normally be gauged with some kind of test.
The common curriculum ensures that every student has a similar baseline of prerequisite knowledge before going into their major courses and electives. Its goal is to provide students with the basic necessities for a liberal arts education. It should be noted that all modules in the first semester of freshman year not graded, and simply evaluated on an S/U (satisfactory/unsatisfactory) basis. This is not the case for all subsequent common curriculum (CC) modules.
As of now, the first semester of AY2018/19 will involve Literature and Humanities 1, Philosophy and Political Thought 1, Quantitative Reasoning, and Comparative Social Inquiry. Semester 2 will involve Literature and Humanities 2, Philosophy and Political Thought 2, and Scientific Inquiry.
There are three more mandatory modules as part of the CC after freshman year: Scientific Inquiry 2, Modern Social Thought, and any one history module (Historical Immersion). However, the common curriculum is constantly being updated and improved, so this may change in the following years.
For more information about the common curriculum, see this page on the Yale-NUS website: https://www.yale-nus.edu.sg/curriculum/common-curriculum/
The setup is slightly different for people who are taking the Double Degree Program (DDP) with NUS Law, because their choice of electives are more restricted. In year 1 semester 2, DDP students may only pick one elective, since the other elective spot is taken up by a law module (Law and Society). Restrictions of this sort will carry on into sophomore year and beyond for DDP students, since mandatory law modules will decrease the amount of electives that students can take.
For more information about the DDP, see this page on the Yale-NUS website: https://www.yale-nus.edu.sg/curriculum/double-degree-with-law/