Old charm and neighborliness flourish in Vietnamese capital

It's winter in Hanoi, with the sort of damp cold that seems to go straight through you, even though the temperature is in the high 50s. People wear jackets , sweaters and mufflers as they cycle to work. The motorbike is only just beginning to make any inroads here, and private cars are still unknown.

Despite the chill, Hanoi is a lively place. Most notably, it keeps alive a tradition that has faded in many faster-paced, more polluted Asian cities: the street as a social center, almost an extension of the home. People stand there for hours talking or sitting on their steps doing chores, such as preparing vegetables for meals. For the seamstresses and workers in the small machine shops, windows opening onto the street seem to take the place of Muzak or television.

Like many medieval cities of Europe - and Hanoi is almost as old as many of them, dating back about a thousand years - some streets are named after the craft practiced or the goods sold there: Silk Street, Basket Street, Dyers' Street.

Some of the streets still keep their ancient identities. While looking for the main market, this writer stumbled over a short street seemingly inhabited only by tombstone makers.

War and poverty have left their mark on the city. Accommodation for many, if not most, Hanoi residents is still squalid. Water often comes from standpipes at street corners, though at least this provides the opportunity for more socializing. (One suggested derivation for the Vietnamese word for ''neighbor'' are the two words ''village'' and ''well.'')

On the other hand, governmental poverty has meant that much of the old French colonial city has survived untouched. If the benefits of French civilization for its colonies tend to be rather overstated by the motherland, the French did leave beautiful cities dotted throughout French Indochina. Hanoi, the capital of the old French colony, is perhaps the finest.

The streets are broad and tree-lined. The houses in the formerly more affluent areas are three- or four-storied, turn-of-the-century, ochre-colored - though today the paint is peeling rather badly. These houses are now embassies and offices, and some Western diplomats have recently been able to move into some of the finer villas, with their their dark-stained wood and ornate fireplaces.

Then there are the lakes around which the city is built, and around which much of its life revolves. Early in the morning retirees do their exercises at the water's edge. Later on young people do their courting there. And most of the day small kids climb the tamarind trees, trying to pick its sour fruits.

Southern Vietnamese tend to feel that northerners are dour and pushy. The harsh climate and poor soil, they say, has deprived them of a sense of humor and the enjoyment of life. To this visitor the northerners are lively and inquisitive, but certainly not dour.

In some ways, Vietnamese in the north are epitomized by the old bas - older ladies usually wearing a business-like tunic, black satiny pants, and a small black turban-like hat that often hides hair that can reach way down their backs. Their teeth are often black, from a practice of lacquering them both to protect them from decay and to beautify them. (The practice died out several generations ago.) Their lips are often red from the betel nut which they chew on constantly.

You see bas in the market, moving at high speed through the crowds or stopping to exchange a bit of raucous gossip with a vendor. They are free with their advice, and they move and talk in double time.

(Two such bas, refugees from the north, lived next door to us in Saigon during the early 1970s, and our open-air kitchens were separated only by a wall. They were avid gossipers, so by standing in the kitchen we could always keep up with the local gossip. When the conversation got too racy or too close to home, our cook would bang on the wall.)

As I wandered past the Lake of the Returned Sword in the center of Hanoi, I happened to pass one bas with her grandson.

''Look at him,'' I heard her say to the child, ''taking pictures all the time!''

I turned around to have a chat with her, and if she was surprised to find a foreigner speaking Vietnamese, she didn't show it. In record time she shot through the standard questions: how old was I, married yet, how many children? She wasn't satisfied with my answer on children. ''Why only one?'' she asked suspiciously.

I told her I was in town for a conference given by her foreign minister. Had she ever seen him? She didn't remember doing so. ''Perhaps he's one of the younger ones,'' she mused. But she did know the prime minister, Pham Van Dong, who seems to have inherited the popularity of Ho Chi Minh.

By this time we had reached her house on the south side of the lake. ''Well you'd better go back to your hotel now,'' she said, noting with disapproval my lack of a sweater. ''It's too cold.''