Python-Code

def languageFormat(sentence):
    i = 0
    while(i < len(sentence)):
        if(isVocal(sentence[i])):
            sentence = sentence[:i] + sentence[i] + "lew" \
                       + sentence[i].lower() + sentence[i + 1:] #replace vocal
            i += 5                                              #jump to next letter of original input
        else:
            i += 1                                              #next letter
    print sentence

def isVocal(letter):
    global vocal
    if letter in vocal:                                         #check if letter is vocal
        return True
    else:
        return False

vocal = ['a', 'e', 'i','o', 'u', 'A', 'E', 'I', 'O', 'U']       #vocal list
try:
    sentence = str(raw_input("Please enter a sentence: "))
    languageFormat(sentence)
except:
    print "Invalid input"