Kittens are usually weaned by six months old. Under natural conditions, mother cats will begin to reduce the amount of milk they nurse and introduce solid food to their kittens when they are about four to six weeks old. By around eight weeks, kittens should be fully weaned and able to eat solid food independently.

If your six-month-old kitten is still not weaned, it could be due to the following reasons:
1. Nutritional Deficiency: If kittens do not receive enough nutrition, they may continue to rely on their mother's milk. Ensure kittens have sufficient opportunities to eat solid food, and that their food is nutritionally balanced.
2. Health problems: Certain health issues can prevent kittens from weaning properly. If you suspect a health problem, it is best to consult a veterinarian.
3. Environmental factors: If the kitten's environment changes too much, such as moving or the introduction of a new family member, it may cause them to feel anxious and thus be unwilling to be weaned.
4. Nursing habits of mother cats: Some mother cats may prolong the nursing period, especially if it is their first litter of kittens, or if there are few kittens.