Rhotic and non-rhotic accent
- A rhotic speaker pronounces the letter "R" in hard and water.
- A non-rhotic speaker does not pronounce it in hard, and may not in water, or may only pronounce it in water if the following word begins with a vowel.
In other words, rhotic speakers pronounce "R" in all positions, while non-rhotic speakers pronounce it only if it is followed by a vowel.
None of the above is absolute, and speakers living in regions where one form or another "dominates" may or may not follow the dominant form.