Hi caniuseit,
There are no fixed rules about how many words may be copied from one copyright work into another before infringement is said to occur. If you were copying lyrics from another song, I would advise great caution, because the music industry is particularly prone to litigation over alleged copying. But as in this case you want to use short snippets of film dialogue within a song, the crossover between two different types of media reduces the risk even more. Clearly the words
hasta la vista are extremely common in Spanish speaking countries and so there is no question of them being considered original enough to attract any copyright. And Robosapien, although much more original, is just a single word, and as such it is also most unlikely to qualify for copyright protection.
The use of trade marks presents a slightly different problem, or perhaps no problem at all. A trade mark is only infringed if it is used in the course of trade, so for instance, in adverts or promotional material or on packaging for a rival product or service. Just using a word like Robosapien
in a song shouldn't cause any problems because it can't be said to be there to promote the sale of something in a way that would confuse the public about the origin of the product. But I do see a problem with using the word as the title of the song because that is the way the song is identified to the public - often in textual form - and therefore genuine confusion could exist if someone was, for instance, searching for a product made by the WowWee Group Limited (owners of the trade mark) and came across your song thinking it was part of the promotional material for WowWee's products, whatever they might be. In fact, in the UK the mark Robosapien is registered in several wide ranging
classes of goods including audio products, which makes your use of the word as a title even more risky.
The same cannot be said for
hasta la vista which as you correctly say is registered in the UK as a trade mark (by a Swedish company called We & Wine AB in
classes 32 and 32 covering beers, wines and spirits). Since your proposed use of something similar to this trade mark would only be buried deep within the lyrics and clearly would normally only be perceived by a listener in aural rather than textual form, that use cannot be said to be in the course of trade, especially when there is a significant difference between a song, and beers, wines and spirits.
The number of times you re-use the words within the song is not really relevant; if they do infringe copyright (and I don't think there is a realistic chance that either of them do) then a single use of the phrase would be sufficient to trigger a claim. Similarly
if it was found that there was trade mark infringement, it wouldn't matter how many time the phrase(s) was used, once would be enough to lead to a claim.
