users_list = [
    ('Александр', 'ru'),
    ('James', 'us'),
    ('Daniella', 'es'),
    ('Someone', 'unknown country'),
]

users_list = [
    ('Александр', 'ru'),
    ('James', 'us'),
    ('Daniella', 'es'),
    ('Someone', 'unknown country'),
]
list_1 = list()
list_2 = list()
for i in users_list:
    list_1.append(i[0])
    list_2.append(i[1])

def res():
    for a in list_2:        
        if a == "ru":
            b = "Привет, "
            print(b, list_1[0],"!", sep="")
        elif a == 'us':
            b = "Hello, "
            print(b, list_1[1],"!", sep="")
        elif a == 'es':
            b = 'Hola, '
            print(b, list_1[2],"!", sep="")
        elif a == 'unknown country':
            b = 'Someone,'
            print(b, list_1[3],"but I do not know where are you from!")
res()                        

  
>>> users_list = [
...     ('Александр', 'ru'),
...     ('James', 'us'),
...     ('Daniella', 'es'),
...     ('Someone', 'unknown country'),
... ]
>>> 
>>> greetings_dict = {
...     'ru': 'Привет, {}!',
...     'us': 'Hello, {}!',
...     'es': 'Hola, {}!',
...     'unknown country': 'Hello, {}, but I do not know where are you from!'
... }
>>> 
>>> print(*map(lambda i: greetings_dict[i[1]].format(i[0]), users_list), sep='\n')
Привет, Александр!
Hello, James!
Hola, Daniella!
Hello, Someone, but I do not know where are you from!
>>>