Suggested answer:
(1) Examples of curb and kerb:
Morgan takes Will's seat as they pull away from the curb.
A big red Italian car was parked at the kerb.
(2) Both nouns can have have the following meaning: "the edge of a pavement or raised path nearest the road", as shown in the two examples above.
(3) To a certain extent the corpus supports that statement. The noun curb is overwhelmingly found in American texts; only a few exceptions were found:
...Sir Harry standing restlessly on the stone curb of the hearth... (from UK text)
In this example, however, the meaning of curb is probably not that of "the edge of a pavement or raised path nearest the road", but rather something like: "any enclosing framework, such as a wall of stones around the top of a well."
Another exception is the following:
...to keep a curb on any particular operation. (from NAM text)
In this case, the meaning of curb is also a different one: "something that restrains or holds back."
As regards kerb, 11 out of 18 occurrences are found in UK text while 6 are found in US texts and 1 in AUS texts. On the basis of the corpus results, then, kerb cannot be said to be a British word.
As a conclusion we could modify the statement and say that, with the sense "the edge of a pavement or raised path nearest the road", curb is typically used in American texts, while kerb is typically used in Britsh texts. However, since curb in this sense is only found in American texts it can be said that it is a more truly American word. Kerb on the other hand, is not shown to be a truly British word to the same extent.
(4) Only curb has been used as a verb in the corpus. This does not mean that kerb can never be used as a verb in English, but it suggests that kerb is less commonly used as a verb than curb. An example of curb used as a verb:
Attempt to curb international trading on human organs...
The meaning of the verb curb is "to control or limit something that is not desirable".
Read about differences between American and British English here
Terminology: noun, verb
Dictionary: Merriam Webster Dictionary
