Q:

Language translation by reading .txt file and print out a translated sentence

I am trying to make a Python program to translate from English to Aboriginal language which reads from dictionary.txt file.
That program should contain pairs of English and translated words separated by a comma (,) and builds a dictionary with them. Program should then read in lines of text from the user (until a blank line) and print out a translated sentence, where each word has been looked up in the dictionary.
dictionary.txt file looks like following:
afternoon,wuraji-wuraji
I,ngaju
bird,jirripirdi
like,kuja-piya
dance,juka-pinyi
python,malilyi
laugh,ngarlarrimi
we,ngalipa

My  program should work like this:
English: I like python
ngaju kuja-piya malilyi
English: we laugh
ngalipa ngarlarrimi
English:

I am so far able to make a program which produces translation for individual words but not the combined sentences. I am just wondering how can I do that?
My code is like following:
user_input = []
translate = {}
for line in open('dictionary.txt'):
        english, aboriginal = line.split(',')
        translate[english] = aboriginal

while user_input != "":
  user_input = input("English: ")
  if user_input == "":
    break
  else:
    print(translate[user_input])

A:

Thank you @JeanRostan for your help, I was able to output correct output with the following code (even though it is very primitive one):  
user_input = []
translate = {}
for line in open('dictionary.txt'):
        english, aboriginal = line.split(',')
        translate[english] = aboriginal

while user_input != "":
  user_input = input("English: ")
  if user_input == "":
    break
  else:
    tempList = []
    for word in user_input.split():
        tempList.append(translate[word])
    A = ("".join(tempList))
    B = (A.replace('\n',' ')) 
    B = B.rstrip()
    print(B)

