The Languages of southeast asia

Thailand, Laos, Burma (Myanmar), Cambodia, Vietnam

The languages of these countries share a number of features, and are entirely different from the group on the right.
Picture
From Adapedia.com
Languages by Country - Country names are in black. Yellow indicates significant languages (over 100,000 speakers in country or widespread).  All other languages are in white.

Burma (Myanmar): Burmese, Shan, Karen, Chin, Akha, Jinghpaw, Mon, Wa, Kayang/Padaung Karen, Lawng/Lao Vo, Naga, Palaung, Tavoyan/Dawei
Click to see full list for Burma (Ethnologue)

Thailand: Thai, Issan (Lao), Shan (Tai Yai), Patani (Jawi/Pasa Yawi/Pasa Melayu Patani) Lisu, Lahu, Hmong, Karen, Yao Mien, Akha (Ekaw), Khmu (K'mu), Khmer, Prai/Lua,              
Regional Dialects: Northern Thai (Pasa Nua or Kam Muang), Southern Thai (Pak Thai)

Laos: Lao, Akha (Ikaw), Bru, Hmong, Yao-Mien, Jeh (Die), Tai Kang, Katang, Khmu (K'mu), Kuy (Dui/Sui), Lahu, Lamet, Brao, Laven (Bolawen), Lu, Mal/Tin, Ngeh, Nyaheun (Niahun), Ong/Tong, Oy (Oi), Phu Thai (Putai), Prai, So/Makong, Thai, Trieng/Ta-Lieng, Ta-Oi, Hani/Hao Bai (Yunnan Chinese).

Vietnam: Vietnamese, Muong, Lu Mien/Dao Do, Bru (Tri Bru), Cao, Cham (Chiem), Chinese - Yue, Chru (Choru), Chinese - Hani, Hre, Jeh, Katu, Kayong (Kagiong), Khmu, Kim Mun/Dao Ao Dai, Koho, Ma/Che Ma, Mnong (Bu Dang, Bu Na, Bu Rung, Dih Bri, Preh), Nung/Bu Nong, Phuang (Puang), Rade/De, Rai/Roglai, Sedang/Dang, Xtieng, Ta Oi, Tay (not Thai), Cuoi/Keo, Trieng/Ta-Lieng, Nung Chao

Cambodia: Khmer, Vietnamese, Cham, Jarai (Chaw), Krung (Brao Krung), Kuy, Biat/Bunong
Malaysia, Indonesia, Singapore, Brunei, Philippines, E. Timor

The languages of these countries have many similarities and are completely different from the group on the left.
Picture
From lardbucket.org
Major Languages by Country

Malaysia: Malaysian (Bahasa Melayu),

Singapore: Malaysian, Chinese - Mandarin, Min Nan (Hokkien, Teowchew, Hunanese), Cantonese - English, Tamil, Tagalog, Baba (Chinese-Malay), Other Chinese - (Min Bei, Hakka, Min Dong (Fuchow) - Hindi, Panjabi, Sindhi.

Brunei: Malay, English, Brunei Kadalan (Kampung Ayer), Bisaya Brunei (Bisaya Bukit), Chinese - Min Nan, Mandarin, Min Dong, Cantonese, Hakka - Iban (Dayak laut), Tutong.

Indonesia: Bahasa Indonesia, Javanese, Sundanese, Balinese. Acehnese, Batak, Betawi, Madurese, Bugis, Sasak, Chinese - Mandarin, Min Nan, Hakka - Tukang Besi, Uab (Atoni) Meto (Timorese), Toraja (Sadan)/Mamasa, Tolaki, Bajau, Tae (Luwu/Rongkong).  Sangih, Osing (Banyuwangi), Palembang (Musi), Minangkabau (Padang), Mandar (Majane/Mamuju), various Malay dialects (Ambon-Kutai), Basa Kupang, Lampung,  Kambera (Sumba Timur), Ledo/Ado/Doi (Palu), Gorontalo, Ekari (Kepauku), Dani. Hundreds of less-spoken languages.

East Timor: Portugese, Bahasa Indonesia, Tetun, Mambae, Kemak-Nogo, Baikenu (Uab Meto).

Philippines: Filipino/Tagalog, English, Cebuano/Visayan, Waray, Ilocano, Chavacano, Sug/Tausug/Sulu, Pampangan, Bicol, Hiligaynon, Maguindanao, Maranaw, Ibanag-Itawit, Ifugao, Binukidnon, Davawenyo/Kamayo, Manobo/Surigaonon, Masbateno (75% same Hiligaynon), Cuyo, Kalinga, Sama/Bangingi/Lutangan/Simunul, Subanen/Sindangan. Dozens of less-spoken languages.