  Let $A$ be an algebra with fixed set of generators $a_1,\dots,a_s$. $V_A(n)$
be dimension of the space, generated by worlds of length $\le n$ over $a_i$,
$T_A(n)=V_A(n)-V_A(n-1)$. If $T_A(n)<\mbox{Const}$, algebra $A$ is a {\it
boundary algebra}. We describe a normal basis of boundary algebras, i.e.
algebras with small growth.
  Let $\cal L$ be a factor language over alphabet $\cal A$. {\it Growth
function} $T_{\cal L}(n)$ is number of subwords $\cal L$ of degree $n$. We
describe factor languages of small growth such that $T_{\cal L}(n)\le
n+\mbox{const}$.
