I've prepared a list of all the files saved in the SD card (or needed). 

Complete list updated here:

https://docs.google.com/spreadsheets/d/1A5Z_0ZLCWuRMt66E694Saxo3OJwWO3L1QZXkWnyu8mk/edit?usp=sharing

Audio files can be made with online services like this:

https://murf.ai/

Some thought is required on the syntax of the sentences...

FOLDER\FILE      MESSAGE

01\000.mp3 =     "00"
01\001.mp3 =     "01"
01\002.mp3 =     "02"
01\003.mp3 =     "03"
01\004.mp3 =     "04"
01\005.mp3 =     "05"
01\006.mp3 =     "06"
01\007.mp3 =     "07"
01\008.mp3 =     "08"
01\009.mp3 =     "09"
01\010.mp3 =     "10"
01\011.mp3 =     "11"
01\012.mp3 =     "12"
01\013.mp3 =     "13"
01\014.mp3 =     "14"
01\015.mp3 =     "15"
01\016.mp3 =     "16"
01\017.mp3 =     "17"
01\018.mp3 =     "18"
01\019.mp3 =     "19"
01\020.mp3 =     "20"
01\021.mp3 =     "21"
01\022.mp3 =     "22"
01\023.mp3 =     "23"
01\024.mp3 =     "24"
01\025.mp3 =     "25"
01\026.mp3 =     "26"
01\027.mp3 =     "27"
01\028.mp3 =     "28"
01\029.mp3 =     "29"
01\030.mp3 =     "30"
01\031.mp3 =     "31"
01\032.mp3 =     "32"
01\033.mp3 =     "33"
01\034.mp3 =     "34"
01\035.mp3 =     "35"
01\036.mp3 =     "36"
01\037.mp3 =     "37"
01\038.mp3 =     "38"
01\039.mp3 =     "39"
01\040.mp3 =     "40"
01\041.mp3 =     "41"
01\042.mp3 =     "42"
01\043.mp3 =     "43"
01\044.mp3 =     "44"
01\045.mp3 =     "45"
01\046.mp3 =     "46"
01\047.mp3 =     "47"
01\048.mp3 =     "48"
01\049.mp3 =     "49"
01\050.mp3 =     "50"
01\051.mp3 =     "51"
01\052.mp3 =     "52"
01\053.mp3 =     "53"
01\054.mp3 =     "54"
01\055.mp3 =     "55"
01\056.mp3 =     "56"
01\057.mp3 =     "57"
01\058.mp3 =     "58"
01\059.mp3 =     "59"
01\060.mp3 =     "minutes"
01\061.mp3 =     "hours"
01\062.mp3 =     "and"
01\063.mp3 =     "alarm set in"
01\064.mp3 =     "AP activated, check Vintagephone in wifi networks"
01\065.mp3 =     "You had set an alarm at this time"
01\066.mp3 =     "Hours or minutes not valid"
01\067.mp3 =     "It is"
01\068.mp3 =     "It's been"
01\069.mp3 =     "alarm set at"
mp3\0000.mp3 =     "line available"
mp3\0001.mp3 =     "connection lost/ended"
mp3\0002.mp3 =     "voice mail sound"
mp3\0003.mp3 =     "busy line"
mp3\0004.mp3 =     "line available"
mp3\0005.mp3 =     "busy line"
mp3\0006.mp3 =     "line available"
mp3\0007.mp3 =     "line available"
mp3\0008.mp3 =     "line available"
mp3\0009.mp3 =     "line available"
mp3\0010.mp3 =     "modem/fax"
mp3\0011.mp3 =     "modem/fax"
mp3\0012.mp3 =     "the dialed number is not available"

TO BE RECORDED:
                     "restarting wemos"
                     "alarm deleted"
                         "Time updated from internet"
                     "Missing wifi