These composed verbs, whose meaning depend on the modifiers, are definitely confusing.
You can go a long way without mastering them, and their meaning (assuming there's only one) isn't always easy to infer from the roots. Think of getting off, for example.
Some of the combinations are still not part of my passive vocabulary[1], and most are not part of my active vocabulary, because I can usually get away with synonyms.
For this scenario, "log in" and "register" offer the best syntactic contrast, and should be favored, IMO. "Sign in" and "sign up" require more thinking. Pet peeve of mine, actually.
[1] There was a vocabulary depth study posted here on HN a while ago, I was at the 95th percentile of non-native speakers, equivalent to the median of natives of my age.
Sign in/out/up in English correspond to actions you might take in your daily life (eg signing in to a visitors' book at a meeting), whereas most people would only have come across log in within a computer related context.
Many non-native English speakers primarily get in contact with English in computer related contexts since they live in a non-English speaking country and use English language websites.
This group of customers may be larger than the group of native speakers depending on your target audience. So optimizing for non-native English speakers living in non-English speaking countries is something which should be considered.
These composed verbs, whose meaning depend on the modifiers, are definitely confusing.
You can go a long way without mastering them, and their meaning (assuming there's only one) isn't always easy to infer from the roots. Think of getting off, for example.
Some of the combinations are still not part of my passive vocabulary[1], and most are not part of my active vocabulary, because I can usually get away with synonyms.
For this scenario, "log in" and "register" offer the best syntactic contrast, and should be favored, IMO. "Sign in" and "sign up" require more thinking. Pet peeve of mine, actually.
[1] There was a vocabulary depth study posted here on HN a while ago, I was at the 95th percentile of non-native speakers, equivalent to the median of natives of my age.