Original mantras, meaning of first few parts of Chandogya Upanishads are available in the link below published in Scribd. This is written in Bengali (Bangla) language following the preaching received( from the seer Shri. Bijoykrishna Chattopadhaya(1875-1945) and his principal disciple Shri.Tridibnath Bandopadhaya(1923-1994). (Debkumar Lahiri).

http://www.scribd.com/doc/38248190/Chandogya-Brahma-Khanda-A-preface-to-Chandogya-Upanishad

http://www.scribd.com/doc/37942944/Chandyogya-Upanishad-Bengali-Translation

http://www.scribd.com/doc/38012976/Chandogya-Upanishad-3rd-part-of-First-Chapter-in-Bengali-language-with-annotations

http://www.scribd.com/doc/38243158/A-Bengali-translation-of-Chandogya-Upanishad-First-chapter-4th-5th-and-6th-Parts

http://www.scribd.com/doc/49775135/Chandogya-Upanishad-1st-Chapter-7th-Part-in-Bengali-with-original-mantras-and-translation-in-Bengali-Language

http://www.scribd.com/doc/62259146/Chandogya-Upanishad-in-Bengali-language-1st-Chapter-8th-and-9th-Part

http://www.scribd.com/doc/84285347/Bengali-version-of-Chandogya-Upanishad-First-Chapter-10-and-11th-part-Tales-of-Ushasti