Thailand has dropped 11 spots in the proficiency rankings for non-native English speaking countries.

The kingdom is now ranked 64th among the 88 listed countries and territories in the EF English Proficiency Index 2018. This year's ranking, conducted by Switzerland-based Education First, a language school operator with branches worldwide, is based on test data from 1.3 million adults who took the EF Standard English Test (EF SET) last year.

In the latest results, Thailand has a score of 48.54, which is classified as low proficiency.

In 2017, Thailand was 53rd (49.7) out of 80 countries and was also categorised in the low proficiency band.

In East Asia, Thailand has the worst English proficiency except for Cambodia and Myanmar. Thailand is far behind China and Japan, which supposedly have low abilities in English.

Sweden tops the EF English Proficiency Index 2018 with 70.7, bumping last year's top-scorer, the Netherlands (70.3), into second place. Singapore ranked third with 68.6 followed by Norway (68.3) and Denmark (67.3).

Libya is ranked at the bottom with a score of 39.64 behind Iraq (40.8), Uzbekistan (42.5), Cambodia (42.8) and Afghanistan (43.6).

Among Asian countries, Singapore was top, followed by the Philippines in 14th, Malaysia in 22nd place, India in 28th, Hong Kong in 30th, South Korea in 31st, Vietnam in 41st, Macau in 44th, China in 47th, Taiwan in 48th and Japan in 49th.

One of the key findings according to the survey is that English proficiency has not improved in Asia despite high levels of investment in the language.

Education Minister Teerakiat Jareonsettasin said that the development of Thai students’ English skills is crucial and needs serious improvement.

"Each Thai student studies English for at least 12 years at primary and secondary school, but most remain unable to communicate in English. This is the main obstacle to global competition," he said.

The two main challenges that need to be addressed are Thai teachers’ English skills and their teaching approach, according to Mr Teerakiat.

By focusing on language accuracy and memorisation rather than communication, most Thai students are left unable to converse effectively in English. Many Thai students were also found to have a poor attitude towards English classes.