The usual approach to teaching a toddler colors is to hold up a card and ask them to say the color back. It feels productive, but it often skips the step that actually has to come first — and skipping it is why so many toddlers seem to "know" colors one day and forget them the next.
Receptive before expressive
Language development has a well-established order: children understand far more than they can say, for every word and every concept, not just colors. A toddler usually recognizes "the red one" correctly long before they can answer "what color is this?" on demand. Drilling the second skill before the first one is solid is like asking someone to perform a word in a language test before they've actually learned to recognize it. It often produces something that looks like knowing the word, propped up by memorizing the specific card, that falls apart the moment the object changes.
What this looks like in practice
Instead of "what color is this?", try "can you find the red one?" — and offer a small group of objects to choose from, not just one. This is receptive recognition: pointing, choosing, matching. It's lower-pressure, it's where real understanding actually starts, and it's testable in a way that doesn't put a toddler on the spot.
Only after a child can reliably find a color across several different objects — not just one familiar card — does it make sense to start asking them to name it. Naming is the harder, expressive half of the skill, and it should come second.
The discrimination trap
One detail that trips up a lot of homemade color activities: if you're testing whether a toddler can find "the red one," don't surround it only with colors that look nothing like red. A red apple next to a yellow banana and a blue block is too easy to get right by accident. A real test includes at least one close, easily-confused color nearby — red next to orange, for instance — so you're actually checking whether they know red, not just whether they can rule out colors that are obviously different.
This receptive-before-expressive sequence, including the discrimination arrays most home activities skip, is the structure My First Colors is built around — using real photographed objects so what your toddler learns on the page actually transfers to the kitchen table and the toy bin.