Looking at these phrases, you can see that the sentences can be split into two types. There is a version using ti which is informal and a formal version using le.
In general, you use the Italian formal word le when speaking to someone older, in authority, with status or to whom you are showing respect.
Now regardless of whether you choose to use ti or le, the sentences constructed using the verb presentare are formal.
A less formal way of introducing other people is Questo è ... (this is intoducing a man) and Questa è ... (this is intoducing a woman).
And finally, we have Lui è ... and Lei è ... meaning 'he is ...' and 'she is ...' respectively.
You can use these less formal phrases with some of the vocabulary that you have already learnt above.
For example, Questa è Marcella, mia figlia 'This is Marcella, my daughter', or Questo è Seth, mio figlio 'This is Seth, my son'.
One thing to keep in mind if you are getting more fancy with your introductions is the need to use the definite article. This is used when you are more descriptive, as in the examples below.
Questo é il mio ragazzo Bert 'This is my boyfriend Bert'.
Questa é la mia amica Marcella 'This is my friend Marcella'.
In fact, the rule is that the definite article (il, or la) is needed when talking about a person (apart from family members).
For example, in the sentence Mia sorella è venuta a trovarmi martedì 'My sister visited on Tuesday' there is no definite article.
A few first words. 1, A few first words. 2, Bedroom items, Buying things. General phrases. 2, Buyings things. Useful words, Clothing, Countries, Communication problems, Conversation. Introductions, Conversation. Small talk. 1, Conversation. Small talk. 2, Conversation. Filler words, Conversation. Small talk. Sport, Conversation. Small talk. The weather, Days. General, Days of the week and seasons, Describing things. Colours, Describing things. Adjectives, Directions. 1, Directions. 2, Eating phrases. 1, Eating phrases. 2, Eating items, Emergencies, Family and people, Food and drink. At the bar or café. 1, Food and drink. At the bar or café. 2, Food and drink. At the bar or café. 3, Getting around. General words, Getting around. General phrases, Getting around. Train and bus, Getting around by taxi, Getting around by car, Health, Household items, Money, Months of the year, Numbers. 1 to 10, Numbers. 11 to 20, Numbers. 30 to 1000, Parts of the body, Places and buildings. 1, Places and buildings. 2, Question and size words, Special occasions, Sightseeing, Somewhere to stay. 1, Somewhere to stay. 2, Sport, The house, Useful words, Useful words to recognize, Words to do with food. Fruit, Words to do with food. Vegetables, Words to do with food. Meat, Time.