Guatico...
No I appreciate this, private pilots cannot all be expected to master English in the relatively short time that it takes to aquire a PPL.... I have no phobias about language.. only safety ! In the situation you describe the controller should take care to ensure that the foreign pilot using English is kept aware of the other traffics' movements to ensure situational awareness...
It ads to the radio traffic which is an extra burden but this is preferable to the horrendous consequences of a collision.