Did the Buddha teach the four noble truths to laypeople?

It's impossible while dwelling in a household to gain path and fruits, even if the Dhamma of the Noble Ones is taught.

Only in "Borderlands" is it possible to gain access to the Four Noble Truth in a liberating manner:

A "borderland" is a "state" between home and homelessness, outer lands and noble domains, outwardly and inwardly.

A monastery, traditional Wat (pi: vatta ) is outwardly a borderland, sometimes called Wat-Aram, (derived from ārammaṇa ).

What ever can be used as a country, whether outwardly (place, room, country, single person, group, society) and inwardly, ways of thinking and perceiving upholds and praises

It's impossible in "Outer Lands", dwelling in a household. So for now important: "When one is born in outer regions", if able to find some rest of old merits, able in erecting faith, one should put all efforts to trace borderlands, get familiar to it and maybe change one's dwelling totally to where access to the Noble Domain could be gained, the four Noble Truth can be fully penetrated.

Maha Mangala Sutta

Yes, the Buddha did teach the four noble truths to lay people.

From SN 42.7:

“Sir, doesn’t the Buddha live full of compassion for all living beings?” “Yes, chief.” “Well, sir, why exactly do you teach some people thoroughly and others less thoroughly?”

“Well then, chief, I’ll ask you about this in return, and you can answer as you like. What do you think? Suppose a farmer has three fields: one’s good, one’s average, and one’s poor—bad ground of sand and salt. What do you think? When that farmer wants to plant seeds, where would he plant them first: the good field, the average one, or the poor one?” “Sir, he’d plant them first in the good field, then the average, then he may or may not plant seed in the poor field. Why is that? Because at least it can be fodder for the cattle.”

“To me, the monks and nuns are like the good field. I teach them the Dhamma that’s good in the beginning, good in the middle, and good in the end, meaningful and well-phrased. And I reveal a spiritual practice that’s entirely full and pure. Why is that? Because they live with me as their island, protection, shelter, and refuge.

To me, the laymen and laywomen are like the average field. I also teach them the Dhamma that’s good in the beginning, good in the middle, and good in the end, meaningful and well-phrased. And I reveal a spiritual practice that’s entirely full and pure. Why is that? Because they live with me as their island, protection, shelter, and refuge.

To me, the ascetics, brahmins, and wanderers who follow other paths are like the poor field, the bad ground of sand and salt. I also teach them the Dhamma that’s good in the beginning, good in the middle, and good in the end, meaningful and well-phrased. And I reveal a spiritual practice that’s entirely full and pure. Why is that? Hopefully they might understand even a single sentence, which would be for their lasting welfare and happiness.

From MN 56:

Then the Buddha taught the householder Upāli step by step, with a talk on giving, ethical conduct, and heaven. He explained the drawbacks of sensual pleasures, so sordid and corrupt, and the benefit of renunciation. And when he knew that Upāli’s mind was ready, pliable, rid of hindrances, joyful, and confident he explained the special teaching of the Buddhas: suffering, its origin, its cessation, and the path. Just as a clean cloth rid of stains would properly absorb dye, in that very seat the stainless, immaculate vision of the Dhamma arose in Upāli: “Everything that has a beginning has an end.” Then Upāli saw, attained, understood, and fathomed the Dhamma. He went beyond doubt, got rid of indecision, and became self-assured and independent of others regarding the Teacher’s instructions. He said to the Buddha: “Well, now, sir, I must go. I have many duties, and much to do.” “Please, householder, go at your convenience.”

Ugga, a rich layman, said in a sutta of the aṭṭhaka-nipātā (AN 8.22):

With confident heart I paid homage to the Buddha. The Buddha taught me step by step (anupubbikakathā), with a talk on giving, ethical conduct, and heaven. He explained the drawbacks of sensual pleasures, so sordid and corrupt, and the benefit of renunciation. And when he knew that my mind was ready, pliable, rid of hindrances, joyful, and confident he explained the special teaching of the Buddhas: suffering, its origin, its cessation, and the path. Just as a clean cloth rid of stains would properly absorb dye, in that very seat the stainless, immaculate vision of the Dhamma arose in me: ‘Everything(suffering) which is arise by the origins(samudaya), has an end.’ I saw, attained, understood, and fathomed the Dhamma. I went beyond doubt, got rid of indecision, and became self-assured and independent of others regarding the Teacher’s instructions. Right there I went for refuge to the Buddha, his teaching, and the Saṅgha. And I undertook the five training rules with celibacy as the fifth. This is the second incredible and amazing quality found in me.

After listening anupubbīkathā ("step by step"), some listeners can enlighten dhammacakkhuṃ ("dhamma eye"), i.e. from the Sāmaññaphalasuttaṃ (DN 2):

So King Ajatasattu, delighting and rejoicing in the Blessed One's words, rose from his seat, bowed down to him, and — after circumambulating him — left. Not long after King Ajatasattu had left, the Blessed One addressed the monks: "The king is wounded, monks. The king is incapacitated. Had he not killed his father — that righteous man, that righteous king — the dustless, stainless Dhamma eye would have arisen to him as he sat in this very seat."

You can find more results by yourself by researching the words dhammacakkhu and anupubbika.

There are many places like that in the tipitaka: so the Buddha did exactly teach the four noble truths to the lay.

The required questions are:

1. What is anupubbīkathā?
2. Why Buddha often taught anupubbīkathā to a lay?
3. Why the first saṅgāyanā monks have to separate anupubbīkathā as many partitions?
4. Why some people think Buddha never taught meditation to a lay?

1. What is anupubbīkathā?

Anupubbīkatha:

1. In pāli canons, it is the sequential teaching or teaching step-by-step. It can be a story or history. See the search results from tipitaka and atthakathā.

2. In tipitaka context, it is a single-time teaching of the entire instructional sequence. It is the very long sutta which describes a buddhist practitioner's procedure, for example:

   • The single-time teaching of Nidhikaṇḍaṃ (Kp 8) (with some commentary)
   • Plus Uposathasuttaṃ (AN 3.70) (with some commentary)
   • Plus Sāmaññaphalasuttaṃ (DN 2) (with some commentary).

You can see that is over long to orally recite.

2. Why Buddha often taught anupubbīkathā to lay?

Buddha taught anupubbikathā to everyone, not only lay, because every practitioner must practice step by step. No one can practice without sequence like a fog -- see Kīṭāgirisutta (MN 70, number 238):

Mendicants, I don’t say that enlightenment is achieved right away.

However for a newbie lay who is genius, buddha taught him from the beginning step to the end in single time -- such as single-time teaching of Kp 8 plus AN 3.70 plus DN 2 (as referenced above).

You can see that is over long to orally recite.

That's why we can't find the single sutta of anupubbīkathā, in tipitaka context, or even in atthakathā as well. So, in atthakathā comment of anupubbīkathā:

Anupubbīkathā is sequence of teaching and commentary of dāna subjects then sīla subjects then heaven subjects then practitioner's procedure.

But the buddha and teacher taught a shorter and more complex sutta to the insider lay man and lay woman (upāsaka and upāsikā), because they have enough ability and knowledge to learn the higher level, e.g. Dānasutta (AN 7.49). You can see that sutta is shorter and more complex, included only charity and the Path. It is anupubbīkathā, but it is not the meaning of "anupubbīkathā" word in the context like AN 8.22.

3. Why the first saṅgāyanā monks have to separate anupubbīkathā as may partitions?

The first saṅgāyanā monks chose "anupubbikathā" words to avoid the over long of sutta. Because most lay people at that time didn't have much knowledge for enlightenment, the buddha had to teach them very long suttas (maybe longer than a DN sutta) and mix many contents to let them enlighten as sotāpanna, or trust to dhamma. So, if the first saṅgāyanā monks didn't separate it to be many smaller sutta, it would have been too long and unable to study by oral recitation.

The evidence from netti vicayahārasampāta:

587. Herein, the Lord Buddha advises one of keen faculties with advice in brief; the Lord Buddha advises one of medium faculties with advice in brief and detail; the Lord Buddha advises one of blunt faculties with advice in detail.

4. Why some people think Buddha never taught meditation to a lay?

Because they are misunderstanding of anupubbikathā. And they don't know how to read teaching as four noble truth, because they never memorize Nettipakarana, or never attained any professional knowledge, ñāṇa, from tipitaka-memorizer and jhānalābhī school, such as Pa-Auk.

Every noble one must enlightened four noble truth, but it is not every ordinary people can discover the noble truth from tipitaka. People who can understand the noble truth from tipitaka must deconflict every uncleared word of tipitaka. This is not feasible for people who can't memorize tipitaka pali and netti, because it needs nirutti-paṭisambhidā to deconflict the whole tipitaka.

For the example from VN Mahāvagga by assachi arahanta to sāriputta, who enlightened as sotāpanna:

Ye dhammā hetupabhavā (dukkha) tesaṃ hetuṃ (samudaya) tathāgato āha
tesañca yo nirodho (nirodha&magga) evaṃvādī mahāsamaṇo.

‘Those things(suffering) which proceed from a cause, of these the Truthfinder has told the cause(origin), And that which is their stopping (cessation&path)— the great recluse has such a doctrine.’”

Or in Sāmaññaphalasuttaṃ, which king Ajātasattu almost enlightened as sotāpanna, it is included vipassanāñaṇa part (brief dukkha), pubbenivāsānussatiñāṇa+cutūpapātañāṇa (extended dukkha), āsavakkhayañāṇa (samudaya+nirodha), and all practitioner's procedures in this sutta are magga.

All above is the example of how to read the noble truth in tipitaka.