1. The song "Happy Birthday to You" is sung in most English-speaking countries during birthday celebrations. It is believed to have originated in the late 19th century in the United States.

2. The traditional birthday cake is highly decorated and can come in various shapes, sizes, and flavors. It is often covered with frosting, icing, or fondant, and may feature designs, patterns, or personalized messages. The decorations on the cake can be tailored to the birthday person's preferences or interests.

3. The number of candles on the birthday cake typically represents the age of the person celebrating their birthday. Each candle corresponds to one year of their life. For milestone birthdays, special candles in the shape of numerals may be used to signify the specific age (e.g., a numeral 5 candle for a 5th birthday).

4. Before cutting the birthday cake, it is common for the person whose birthday it is to make a silent wish. They typically take a moment to think about their wish before blowing out the candles. According to tradition, if all the candles are extinguished in one breath, the wish is believed to come true. It is customary for the birthday person to keep their wish a secret.

5. Typical birthday party decorations include balloons, streamers, and confetti. Balloons are often hung or scattered around the party area, while streamers may be used to create colorful backdrops or hang from walls and ceilings. Confetti, small pieces of colored paper, is often thrown or scattered during the celebration to create a festive atmosphere. Other decorations like banners, signs, and table centerpieces may also be included.