No matter what is your mother tongue language if you want to learn the easiest spoken language in the world, the answer is Bahasa Melayu. Easy grammar and easy pronunciation.
Bahasa Melayu normally written in Latin/Romance alphabet called Rumi and used to be written in Arabic called Jawi. Everyone can read Rumi so it's easier for you to learn Bahasa Melayu. One more thing, the sound for each alphabets, words and sentences in Bahasa Melayu is as it is. The alphabet 'C' will sound 'C' not 'K'.
It'll be easier to explain with some examples so here we go..
Semalam saya pergi ke kedai runcit (Melayu)
Yesterday I went to grocery store. (English)
Sekarang saya nak pergi ke kedai runcit (Melayu)
Now I want to go to grocery store.(English)
The word pergi never change in Bahasa Melayu whether it's past tense or present tense even for future tense. But in English, you need to change the word 'go' to 'went' for past tense. If you are not Malaysian and curious how the word pergi readed, you only need to say it as it is. Malaysian would easily understand what I mean but it's a bit matter for outsider but it's OK. Here another example..
Learn Bahasa Melayu Video
OK, now you know what I mean the words in Bahasa Melayu is readed as it is without changing it like English Language. Another simple example is umpan (bait). You just read it as umpan not 'arm-pen' or 'arm-pan'.
Malaysia or known as Tanah Melayu in the past had it's own history of the wide use of Bahasa Melayu. Merchants from Arab, China, India and others who trade in Tanah Melayu they all speak Malay. Even the famous colonial Tanah Melayu come from British, Japan and Portugal know how to speak Malay. At that time, Bahasa Melayu is the international language. All this historical facts are recorded in high school history textbooks in Malaysia. Malaysian who have graduated from high school should know about this already.
Bahasa Melayu has many words borrowed from Arabic, English, Tamil, Chinese, Portuguese etc..A combination from many languages from around the world has made Bahasa Melayu as what as it is now. The combination is a symbolic to the many races in Malaysia other than 3 major races (Melayu, Chinese and Indian), there are African, Arabian, Bangla, Cambodians, Indonesians, Filipinos, Nepalese, Pakistanis, Thais, Vietnamese, Sikhs, South Africans, Nigerians, Singaporeans etc..
Most of them in Malaysia because of occupations. If you live in Johor Bahru, you'll notice Singaporeans always come here for shopping every Sunday. The same thing about all of them is that they know how to speak in Bahasa Melayu.
Finally, I convinced that Bahasa Melayu is the easiest language to learn. The proof is you can see it by yourself that all the foreigners work in Malaysia within 1 year can speak Bahasa Melayu.
p/s: Some old folks said some Arabs trader in Makkah/Madinah can speak Malay.