Because vicino is normally followed by the preposition a when it introduces a noun.
So the pattern is:
That means:
You cannot say vicino il segnalino in standard Italian.
Examples:
So in your sentence:
Al is a contraction of:
This is very common in Italian. Prepositions often combine with definite articles.
Some common combinations:
So:
Segnalino usually means a small marker, token, or counter, especially in games.
It comes from segnale / segnare ideas, and the ending -ino often gives the idea of something small.
So depending on the context, segnalino could be:
In a board-game sentence like this, token or marker is often the most natural translation.
It is:
The basic word order is very normal and natural:
So the sentence follows a simple pattern:
Italian word order is often flexible, but this version is the most straightforward.
You might also hear variations for emphasis, such as:
But that sounds more marked or literary, and it changes the focus. For a learner, Il dado cade vicino al segnalino is the safest and most neutral version.
Here vicino is being used in a fixed expression with a: vicino a = near.
In this use, it does not change to agree with segnalino.
So you get:
However, vicino can also be used as an adjective, and then it does agree:
So there are two useful patterns:
In your sentence, it is the first pattern.
Yes, very often you can.
Both can mean near / next to, but there is a slight difference in feel:
So:
Accanto a can sound a bit more specific, as if the objects are right beside each other.
Vicino a is slightly broader and can simply mean close by.
You usually learn the gender together with the noun:
Both are masculine singular nouns, which is why they use:
Their endings also fit common patterns:
That pattern is not perfect for every noun in Italian, but it is a very useful general rule.
So:
And their plurals are: