The size of a memory module (RAM) is typically expressed in English as follows:

1. Gigabyte (GB):
- For example, a 16 GB RAM module would be referred to as "sixteen gigabytes of RAM" or "a sixteen gigabyte RAM module".
2. Megabyte (MB):
- For smaller memory sizes, the unit of measurement may be megabytes.
- For example, a 4 GB RAM module could also be expressed as "4096 megabytes of RAM" or "a four thousand and ninety-six megabyte RAM module".
3. Terabyte (TB):
- For very large memory sizes, the unit of measurement may be terabytes.
- For example, a 2 TB hard drive could be referred to as "two terabytes of storage" or "a two terabyte hard drive".
So, in summary, the common units used to describe the size of memory modules (RAM) in English are gigabytes (GB) and, less commonly, megabytes (MB). The specific wording would be "[size] gigabytes of RAM" or "[size] megabytes of RAM".