In order by importance in the field of linguistics.

If you are looking to understand something more deeply, here are a number of online options for definitions and explanations.

To access corpora from 2016-present that are available for download: 

1. First, register with LDC using your MIT email address and your current department or lab.
   1. Under "Organization" look for  "Massachusetts Institute of Technology - MIT - Libraries" and select that option from the resulting drop-down menu. Do not use abbreviated form (e.g. "MIT") please type the whole string above to access the correct account.
   2. The libraries will approve your account within one business day. (If you don't receive an email, check your spam filter).
2. After your account is approved, to access data, login to LDC and then go to the downloads tab under "your account options".
   1. The datasets that MIT Libraries has access to will be listed.
   2. If you need a corpus that is only available by hard drive or requires a separate license before download, please email ldc-lib@mit.edu.
   3. If you need a pre-2016 corpus that we don’t have subscription access to, please fill out this form.

For all MIT users, available corpora are listed by year on the LDC site (MIT Libraries’ access to LDC corpora is limited to corpora published from 2016 on). Note that the corpora available as CDs or DVDs from 2016-present can be accessed by individual title through the Library’s Catalog.