import csv

word_list = ["Hello1;;;;World1", "Hello2;;;;World2"]

with open('words.csv', 'w') as new_file:
    csv_writer = csv.writer(new_file, delimiter=',')

    for line in word_list:
        csv_writer.writerow(line.split(';;;;')[0] + "t" + line.split(';;;;')[1])

Hello1, ,World1
Hello2, ,World2

H,e,l,l,o,1,    ,W,o,r,l,d,1
H,e,l,l,o,2,    ,W,o,r,l,d,2