"Immediate changes" must be made to the procedures governing employment of overseas doctors in the NHS, MPs have said.
A Health Committee report urged instant action to improve English language tests as one way of improving patient safety.
Citing the case of German doctor Daniel Ubani, who accidentally killed patient David Gray by administering 10 times the normal dose of diamorphine, the report said: "If the General Medical Council had been able to check the language skills and clinical competence of European Economic Area doctors wishing to practise as GPs, lives might have been saved."
Dr Ubani's poor English meant he was refused work by the NHS in West Yorkshire, only to be accepted in Cornwall, an inquest in February heard.
He admitted being exhausted before starting his shift in the UK, and said he was confused about the difference between drugs used here and in Germany.
"I agree it is vital that the patient understands the doctor and the doctor understands the patient. This should be extended to all clinical staff working in primary care, hospitals and nursing homes" – Anna Richardson, Essex