YouTube tutorial on how to draw diagrams (linguistic trees) using LaTeX

main.tex

\documentclass{article}

\usepackage{forest}

\begin{document}

\pgfmathsetseed{14285}

\begin{center}
    \begin{forest}
        random tree/.style n args={3}{% #1 = max levels, #2 = max children, #3 = max content
        content/.pgfmath={random(0,#3)},
        if={#1>0}{repeat={random(0,#2)}{append={[,random tree={#1-1}{#2}{#3}]}}}{}},
        before typesetting nodes={for tree={draw,s sep=2pt,rotate={int(30*rand)},l+={5*rand},
        if={isodd(level())}{fill=green}{fill=yellow}}},
        important/.style={draw=red,line width=1.5pt,edge={red,line width=1.5pt}},
        before drawing tree={sort by=y, for nodewalk={min=tree,ancestors}{important,typeset node}}
            [,random tree={9}{3}{100}]
    \end{forest}
\end{center}

\section{Basic example}
\begin{forest}
    [1
            [2[6]]
            [3
                    [4]
                    [5]
            ]
    ]
\end{forest}

\begin{forest}
    [1[ciao[3][hello user]][2]]
\end{forest}

\section{Children align}
\begin{forest}
    [\LaTeX\ numerals, calign=first
    [arabic[1][2][3][4]]
    [roman[i][ii][iii][iv]]
    [alph[a][b][c][d]]
    ]
\end{forest}

\section{For tree}
\begin{center}
    \begin{forest}
        [\LaTeX\ numerals,
            for tree={calign=first}
                [arabic[1][2][3][4]]
                [roman[i][ii][iii][iv]]
                [alph[a][b][c][d]]
        ]
    \end{forest}
\end{center}

\section{Tier}
\begin{forest}
    [VP,
    [DP[John,tier=word]]
    [V’
    [V[sent,tier=word]]
    [DP[Mary,tier=word]]
    [DP[D[a,tier=word]][NP[letter,tier=word]]]
    ]
    ]
\end{forest}

\section{tikz}
\begin{forest}
    [123,circle,draw=red,line width=1.5pt,fill=yellow
    [DP,draw][V’[V][DP]]
    ]
\end{forest}

\section{Conditional}
\begin{forest}
    where n children=1{tier=word}{}
    [VP
    [DP[John]]
    [V’
    [V[sent]]
    [DP[Mary]]
    [DP[D[a]][NP[letter]]]
    ]
    ]
\end{forest}

\section{Decoration}
\begin{forest}
    [CP
    [DP,name=item 1]
    [\dots
    [,phantom]
    % [VP
    % [DP]
    % [V’
    % [V]
    [DP,draw] 
    {
    \draw[->,dotted] () to[out=south west,in=south] (item 1);
    \draw[<-,red] (.south east)--++(0em,-4ex)--++(-2em,0pt)
    node[anchor=east,align=center]{Comment};
    }
    ]]
    % ]]
\end{forest}

\section{Horizontal}
\begin{forest}
    for tree={grow'=0}
    [{text}
    [1[Federico][Test]]
    [2]
    [3]]
\end{forest}
\\
\begin{forest}
    [1
    [2[6][7]]
    [3,grow'=0
    [4]
    [5]
    ]
    ]
\end{forest}

\section{Preamble}
\forestset{
    default preamble={
            font=\Huge,
            for tree={circle,draw}
        }
}
\begin{forest} [A[B][C]] \end{forest}
\begin{forest} red [D[E][F]] \end{forest}
\begin{forest} for tree={dotted} [G[H][I]] \end{forest}

\end{document}