In thinking about the ways English is evolving, we have to recognize that it is frequently a lingua franca between non-native speakers. This has strange implications for teaching. I have been told that it is not worth learning any standard form of pronunciation because “the people I talk to wouldn’t understand” and I’ve been asked to simplify verbs to eliminate tenses! Of course, as English has developed from a highly synthetic language to an analytical one, it is likely that further losses of inflected forms will occur. I’ve noticed that many speakers prefer not to use the –er ending for comparatives, preferring to add “more” instead: I’m more happy, more free, etc.
But although such changes occur naturally, it isn’t possible to construct a form of the language that suits non-native speakers. Quite apart from the issue of whether such an “international” variety of English is desirable, it would surely be impossible. The hallmarks of the English spoken by people with varying linguistic backgrounds are themselves very different, influenced by mother tongue interference. And as for pronunciation, well in reality native speakers have accents that vary enormously anyway, but some key elements need to be standardized for intelligibility. For example, it is important to distinguish between long and short vowel forms as these alter meaning. And it helps if the consonants or consonant clusters at the ends of words are distinct if listeners are to hear where the word boundaries are. To that extent, we are making concessions to the non-native speaker, because consonants at word boundaries are often elided or merged with the first sound of the next word when native speakers talk at normal speed.
I think we have to remind students that, if English is to be effective in an international setting, it has to have been learnt according to some agreed benchmarks. This is why we teach a standard form such as American or British English. This allows people to improve their language ability in a logical way. Of course, it’s helpful to teach coping strategies: ways of dealing with the gaps in knowledge. If a particular item of vocabulary is lacking then the non-native speaker needs to handle the situation so that communication doesn’t break down. They might use a circumlocution, a mime or even use a word form their own language if they think their interlocutor will understand. Similarly, if they have grammar problems, they can explain that they make errors but express the hope that they can be understood.
Using English internationally, is not, I believe about trying to simplify the language to make it more accessible but about helping users to become ever more proficient as they deepen their knowledge of the variety of English they are learning.